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The Pacific hurricane reanalysis project is a WHFC research project headed by forecaster Yellow Evan as an attempt to re-analyze and update the strengths of intense tropical cyclones in the Eastern Pacific crica 1978-1994. 

HURDAT2 format (1978-1994)

PhasesEdit

  • Phase 1: Review data for intense/notable hurricanes in EPHC era (timeframe to be completed: Summer 2015)
  • Phase 2: Add possible storms in EPHC era (timeframe to be completed: Fall 2015)
  • Phase 3: Review data for intense/notable hurricanes once NHC takes over, and look at all Dvorak estimates (timeframe to be completed: Early 2016)
  • Phase 4: Review landfall intensities (completed: Spring 2016)

PressuresEdit

Before any storms were re-analyzed, default pressures were added and partially based on modern day NHC readings for most storms from 1978-1987 and a few CPHC after that, aircraft readings for intense storms in other basins, and Dvorak 1984 based pressures.

Reanalyzed stormsEdit

1978Edit

Hurricane AlettaEdit

Pressures adjusted to account for rapid deepening near land. Genesis pushed back 12 hours, with center points based on extrapolation. Based on a T4.5 with an eye pattern a T3.0 with a curved band pattern and an EPHC estimate of 35 knts, the intensity at the original genesis time has been changed to 50 knts. The peak intensity was elevated to 70 knts based on a T4.5 and an EPHC estimate of 65 knots. Based on higher than expected surface observations, the intensity has been tweaked upward a bit at later points.

Hurricane CarlottaEdit

At 0000 UTC June 17, the EPHC started the system as a 20 knot TD, which has been revised upwards to 30 knts due to the storm's impressive deep convection. After genesis, intensification appears reasonable, and left largely unchanged. Carlotta, however, has been upgraded to an 65 knt hurricane at 1800 UTC June 18, based on a blend of a T5.0/90 knts (using CDO pttern) and the EPHC estimate of 40 knots. Six hours later, the intensity is estimated to be a possibly conservative 70 knts by the warm spot on the eye and T5.0/90 knts using an eye pattern, and an EPHC estimate of 45 knots. On June 19, the intensity estimates are also raised, based on a 1500 UTC fix that yielded a T4.5 with a curved band pattern. At 0000 UTC June 20, the intensity is increased to 85, due to rising EPHC estimates and a T5.0/90 knt fix based on an eye pattern. Three hours later, these numbers skyrocketed to T6.5/127 knts; however, the 0600 UTC intensity has been elevated to only 105 knts due to lag. At 1200 UTC, the intensity is raised to 115 knots, based on a CF of T6.0/115 knts. At 1800 UTC, the intensity is increased to 120 knots, based on a DT of T6.5/127 knts at 1500 UTC, but lowered to slightly due to the asymmetrical appearance and an 1800 UTC fix of T5.5/102 knts. Due to an apparent eyewall replacement cycle and possible wind shear, the intensity estimate has been lowered for the next few packages, despite CI values of T6.5. At around 0300 UTC June 21, cloud tops re-cooled dramatically, indicating a second period of RI. However, the 0600 UTC has been adjusted to only 125 knts due to the lag of satellite presentation. At 1200 UTC, the intensity has been conservatively raised to 135 knts, despite a 0900 UTC fix of T7.0/140 knts due to uncertainties of resolution, as well as a subsequent warming of the cloud tops. After undergoing another possible eyewall replacement cyclone, the intensity is increased back to 120 knts midday on June 22, based on a comprise of a T6.5/127 knts and an EPHC estimate of T6.0/115 knts. No other changes are made to the rest of the storm's life, aside from some pressure tweaking.

Hurricane DanielEdit

The system has been revised to have become a TS six hours than listed in HURDAT, and no longer weakens this storm to a 25 knt depression late on June 27, rather, a 30 knt TD, based on a CI estimate of T2.0/30 knts. At 0000 June 28, the WFHC brings the intensity back to 35 knt, based on a curved band estimate of T2.5/35 knts. Following a major decline in convection around 0600 UTC, the intensity is lowered back to 30 knts for 0600 UTC. Convection began to rapidly increase on June 22, and by 1800 UTC, the estimate is changed to 55 knts, in agreement with the EPHC. Based on a 1500 UTC fix on June 29 of 4.0, Daniel is classified as a hurricane at 1200 UTC. At 1800 UTC, based on a T4.5 fix at that time, the intensity is raised upwards to 75 knts. Despite fixes of only T4.5/77 knts from both a curved band and CDO pattern, the intensity is increased to 80 knts at 0000 UTC June 30, and 85 knts at the 0600 UTC synoptic time. Ay 1800 UTC, Daniel is increased to 115 knts, a bit below the T6.5/127 knts out of respect to an 100 knts EPHC estimate. At 1800 UTC and 0000 UTC, the intensity has been increased to 120 knts and 125 knts, in between the EPHC estimate and T-numbers of 7.0, despite only a DG eye, due to the impressive CMG ring. The weakening trend has been smoothed out to account for the higher than EPHC estimates, but otherwise, no real changes are made aside from the above.

Hurricane FicoEdit

On July 7, Fico was born as a TD. This is reasonable given the storm's steady >T2.5 appearance maintained throughout the day. The evolution of thew storm appears reasonable, and most of the estimates are unchanged. A large eye structure develops, resulting in major overestimates from the EPHC and the Dvorak clasffication at that time. While the storm looks well-organized on July 8, a 1200 UTC EPHC estimate of 100 knots and a modern-day estimate of T5.5 looks well off, and it's structure more resembles a better looking Hurricane Blanca. Although the storm has been awarded pressures in the 100 knt range, the intensity has been set at 85 knts at 1200 UTC. After 1200 UTC, cloud tops cool uite a bit, though the intensity at 1800 UTC is only 90 knts due to its large size. The eye began to shrink and at 0000 UTC July 12, the WHFC estimates that the storm attained major hurricane intensity, in agreement with a T5.5 estimate. Twelve hours later, the estimate is raised to 115 knts, in agreement with a T6.0. However, the storm maintained a somewhat ragged structure, resulting in slightly lower estimates after noon on July 12, and in compliance with modern day estimates, which ranged from T5.5 and T6.0 over the next several hours. At around 1500 UTC, satellite intensity estimates were a stable 6.0 and as such, the intensity estimate is set at 115 knts, above the 105 knts from the EPHC at the 1200 UTC synoptic time July 13. After that, satellite estimates fell to around 5.5 and stayed there for another day or two (sans a brief increase to T6.0 late on July 14), so the estimates are mostly unchanged. Early on July 15, modern day estimates return to T6.0, so the intensity is slowly increased back to 115 knts, doing so at 1200 UTC July 15. However, an 1800 UTC yielded a DT of 5.5, but a CI value of 6.0, so the intensity was lowered to 110 knts in agreement with the EPHC estimate. A white ring rapidly returns to satellite imagery at 2100 UTC, warranting a DT of 6.5, but due to the storm's large eye and possible lag, the intensity is set at 115 knts. The white ring became less embedded around the eye at 0600 UTC, and as such, the intensity is lowered back down to 110 knts due to a DT of 5.5, but still below CI values. Similar fluctuations like these continued through July 16. After that time, weakening then commenced over cooler waters, and the intensity is reduced to 100 knts since CI values could not support a 6.0 any longer at 0000 UTC. At 09009 UTC, T-numbers fell to 5.0, so the intensity was cut to 90 knts a few hours before that. However, this was short-lived. Early on July 18, T-numbers are according to modern day estimates, to have returned to 6.0/115, so Fico was re-upgraded to an 110 knt major hurricane. Clod tops rapidly re-warmed, and estimates once again fell quite a bit, to 5.0 by 0900 UTC on July 18. No changes are made past this point due to lack of satellite imagery.

Hurricane GilmaEdit

On July 13, a tropical depression that would later become Hurricane Gilma was formed. The EPHC correctly upgraded the depression to a tropical storm later that day. Based on the formation of a CDO, the intensity at 1800 UTC July 14, is increased to 55 knts. Given the impressive CDO, Gilma is increased to a 60 knt storm 6 hours later, despite a T3.5. At 0600 UTC, Gilma is upgraded to a hurricane based on both DT and MET of 4.0/65 knts at 0300 UTC. At 0600 UTC, Dvorak yiedled a T4.5, so the intensity has been increased to 70 knts at 1200 UTC and 75 knts at 1800 UTC. A 0900 on July 15 UTC fix supported an intensity of 90 knts/T5.0, and the intensity is blended with the 0z EPHC estimates to yield 85 knts. No other changes have been made to the HURDAT.

Hurricane HectorEdit

The EPHC's early handling of Hector appears decent, and has been left unchanged. Based on a T3.0 at 1500 UTC, the intensity has been elevated to 45 knts at 1200 UTC. The intensity remains unchanged since it appears that the EPHC had a very good grip on it. At 1200 UTC July 24, the intensity estimate is increased to 80 knts at 0600 UTC and 85 knts at 1200 UTC due to a T4.5/77 knts based on PT, and T4.5.77 knts via a CDO pattern, and since cloud tops were rapidly cooling at the 0900 UTC time of the fix. A 1500 UTTC fixed yielded a B eye and CMG cloud tops for a CF of 6.5/127 knts and a DT of 6.0/115 knts. Based on those data and the EPHC estimate of 70 knts, 100 knts seems like a good value for 1800 UTC, although this could be generous, due to a lag in the wind speeds. Based on increased symmetry and a DT of T7.0/140 knts (adjusted down to an FT of T6.5/127 knts due to constraints at 2100 UTC. Furthermore, a 0000 UTC frame warranted a borderline conservative T7.0/140 knts. However, the eye is not warm enough for me to be comfortable going any higher than 125 knts, not to mention I'm not sure if the satellite presentation has caught up. Further estimates from 0300 and 0600 UTC supported T7.0/140 knts. However, the intensity has only been set at 135 knts since the warm is not warm enough. After peak intensity, only minor changes in pressure and intensity take place.

Hurricane NormanEdit

The EPHC genesis start time has been increased to 35 knt based on an impressive burst of deep convection, and genesis itself has been pushed back 6 hours. The 0600 UTC intensity has been elevated to 45 knts, based on PT of 3.0. Most of the EPHC intensities in early phase genesis appear to be reasonable. Based on the expanding CDO, Norman is awarded 70 knts rather than 65 knots at 1200 UTC September 1, which is reasonable, given the fact that with a CDO pattern, the presentation supports a possible T4.5/77 knts. Given the impressive CDO present, the intensity has been upped to 80 knts at 1800 UTC September 1, slightly above the T-numbers of T4.5/77 knts. At 2100 UTC UTC, a B eye forms embedded in CDG and with a W ring, this supports a DT of T5.5/102 knts. At this time, the intensity is increased to a somewhat uncertain 100 knts. At 0000 UTC, the eye starts to warm, and a 0300 UTC fix granted the system a T6.5/127 knts, with no eye adjustment downward needed. An eyewall replacement cyclone begins thereafter, resulted in a decline in T-numbers to 5.5/102 knts by 0900 UTC. However, during ERC's initially, very little weakening occurs, so the intensity is set at 110 knts at 1200 UTC, about the time the eye caves in. The ERC finishes up shortly after the 1800 UTC frame, when a Dvorak fix yielded a DT of T5.5/102 knts. Owing to the higher CI values of T6.0, the intensity at the time is set at 105 knts. Due to the ragged appearance of the storm, Norman's winds are only set at 110 knts at 0000 UTC, despite a DT of T6.0 at that time. A well-define OW eye develops again at 0600 UTC, and a 0300 UTC estimate supported a DT of T6.0 while a 0600 UTC estimate went with a DT of T6.0, but does not take into account the storm's large eye. The 0600 UTC synoptic time is set tentatively set at 120 knts. The 0900 and 1200 UTC September 3 frame supported a DT of 6.5/127 knts. Judging by the typical evolution of major hurricanes, the satellite presentation likely peaked between the two times, but since the eye seems warmer at 1200 UTC, and there is often some sort of lag in winds, Norman is listed as having 125 knot winds at 1200 UTC. A rapid decay is shown in the revised database, even though the storm had a warm eye and CI values of 6.5 through the day. No other serious changes are made after this time.

1979Edit

Hurricane AndresEdit

Intensity increased just after start of genesis based on DT of T2.5. At 0600 UTC on June 2, the intensity is increased to 40 knts, a bit above the DT of 2.5, since the Dt at previous estimates was 2.0, as well as the fact that MET is 4.0. Six hours later, the intensity is elevated to 45 knts based on a PT and MET of 3.0. At 0000 UTC June 3, intensity is increased to 55 knts, based on a T3.5 via a banding pattern. At 0600 UTC, a PT yielded 4.0 while a curbed band pattern gave a DT of 3.5 while a CDO pattern gave a DT of 5.0. Taking into account EPHC estimates, the intensity is increased conservatively to 65 knts, but elevated further to 75 knts at 1200 UTC based on a blend of the 65 knt EPHC estimate and a bullish DT of 5.0 and PT of 4.5. An eye briefly develops around 2100 UTC, resulting in an eye number of 6.0 and no eye adjustment, but this classification is too high due to its ragged structure. However, this feature dissipation by 000 UTC, resulting in a DT of 5.0 and an intensity estimate of 90 knts at that time. This is also in agreement with surface observations. At 0600 UTC, DT estimates fall to 4.5, but since the CI value is still 6.0, an estimate of 85 knt works then. Shorty thereafter landfall occurs and an inland decay rate is used for the rest of its life cycle.

Hurricane EnriqueEdit

Intensity revised upward slightly based on impressive deep convection from around the time of formation, and event the genesis has been pushed back. At 1800 uTC July 17, the intensity is elevated to 35 knts based on a PT of T2.5, and extended back based on a DT of 2.0, indicating that development must have taken place prior to that time. At 0600 UTC July 18, Enrique's winds have been raised to 45 knots (and 40 knts based on a similar structure at 0000 UTC) based on a DT of 3.0. At midday, a DT supports a T4.0, but the actual estimate is weighted in with the EPHC estimates for an intensity of 55 knts at 1200 UTC and 60 knts at 18z. At 0z, despite a decline in convection, intensity estimates support a T4.0/65 knts, and that is being uses as the intensity and is in good agreement with the EPHC estimates. Little change in strength is noted as dry air prevented an inner core from fully forming for a while. At 1200 UTC, a Dt of 4.5 is dervied by a LG width in a CDO pattern, but with a curved band pattern, one would likely get either a T4.0 or T4.5. Hence, the intensity is incrreased to 70 knts at 1200 UTC, even though this estimate is likely conservative. However, around 1800 UTC, DT estimates fell to 4.0, so the intensity is lowered to 65 knts again. Deep convection rebuods near the center at 0000 UTC Jluy 20, so based on a DT of 4.5, even though with a curbed band pattern, a DT of 3.5 looks more reasonable, the intensity is held at 65 knts. Northwesterly shear took toll on the system, and a cured band DT fell to 3.0, while the CDO DT remained 4.5. The 0600 UTC splits the difference, and lowers to the intensity to 55 knts. A curbed band estimate of 3.0 from 1800 UTC supports lowering the intensity to 45 knts, but owing to CI values and EPHC estimates, the intensity is set to 50 knts. A 0000 UTC DT of 350; however, supports increasing the intensity back to 55 knts. At 1200 UTC, a DT is 4.0 using an eye pattern. A banding eye rapidly becomes visible thereafter. and at 1800 UTC, a DT of 5.5 was awarded. Due to lag and the banding structure, the intensity was set at 85 knts. At 2100 uTC, a clear WMG eye develops, and a DT of 6.0/115 knts seems fair at 0000 UTC July 22, when the intensity is increased to 115 knts. Even though DT values thereafter never get higher than T6.0, the intensity peak is kept at 125 knts in agreement with the EPHC and due to the presence of a WMG eye. The rest of Enrique's life remains unchanged.

Hurricane IgnacioEdit

Tropical Storm Ignacio formed midday on October 23, with an 1800 fix showing it as a 35 knt TS, based on a DT of 2.5 at that time. A CDO quickly develops, and as such estimates in the file are raised. At 1200 UTC October 24, the intensity is increased to 55 knts based on a DT of 3.5. After a brief pause in intensification, a DT of 0000 UTC October 25 and ar 6z supported a T4.0 and either a T4.5 (with curved band) or T5.0 (with CDO), so the intensity at the representative times is set at 65 knts and 75 knts, well above EPHC estimates. By 1200 UTC, the estimates in increased to 80 knts to account for the same 0600 estimates being retained at 1200 UTC. Some decrease in banding features is noted, so the intensity is kept constant for the resat of the day. At 0600 UTC, an episode of RI started, and DT equaled to T6.0/115 knots. However, due to lag, the intensity is set at 100 knts. At 12z, the DT remained T6.0/115 knts, so the WhFC increases the estimate to to 115 knts. The estimates remained unchanged at 18z, and so is the intensity. At 0000 UTC October 27, some decline in satellite presentation is noted, as the eye cools and the intensity is lowered to 105 knts based on a blend of PT of 5.0, CI values of 6.0, and a DT of 5.5. Six hours later, the eye clears out, and a DT of T6.5 is noted. However, since the eye is not warm enough, an intensity of 120 knts is probs generous. A 0900 UTC analysis yieled a Dt of 6.5; however, a 1200 UTC analysis supported a DT of 7.0, even though this estimate looks generous, due to a eye of only around 9C and a W ring is barley a .5 across. In addition, using a VIS classification, one gets only a 6.0. Given that a reconnaissance aircraft found winds of 125 knts and 938 mbar six hours later, when the white ring broke on the left side, and the eye became more circular, but slightly cooler and IR DT then was at best 6.0/115 knts, 130 knots is the estimate intensity. During the weakening phase, only slight changes are made.

1980Edit

In addition to the below, small tweaks were made to Blas and Celia, some of it smoothing, and in some cases based on Dvorak, genesis or intensification was pushed upwards.

Hurricane AgathaEdit

The way the EPHC handled the start of genesis was reasonable along with the start time. Based on PT=2.5 at 0z June 9 and a possible DT of 2.5 six hours later, the 6z intensity is set at 35 knts. The 12z intensity is 40 knts based on an increase in convection. At 1800 UTC June 9 and 0000 UTC June 10, DT=3.5/55 knts, so the intensity is changed to 50 knts with a compromise of the EPHC estimate. A burst of convection occurs south of the center and due to the development of a CDO, the 6z June 10 intensity is 55 knots. At 18z, a VIS analysis of DT supported T4.0/65 knts, in agreement with PT of both EIR and PT. In respect to an EPHC estimate, 65 knts is a good estimate. A 0000 UTC June 11 estimate favored an intensity of T4.5.77 knts using a CDO pattern, but a data-T number of T3/55 knts was derived from a curved band pattern. As a somewhat generous comprise of that and the EPHC estimate of 70 knts, 70 knts is a good estimate. Based on a 12z blend of VIS curbed band Data=T's of T4.5/77 knts and a CDO pattern of T5.0/90 knts, the intensity at 6z is set to 75 knts, only slightly above the EPHC estimate based on similar presentation there and to 80 knts at 12z. An eye forms at 18z so the intensity is nudged to 85 knts then. A 0z DT supported T5.0/90 knts (largely due to an 95% but not 100% complete black ring), but PT and MET is at T5.5/102 knts, the intensity remains a possibly generous 100 knts. The reminder of the post peak-life is mostly unchanged.

Hurricane HowardEdit

DT of T2.5 on 0z July 31 supports not only pushing genesis but an intensity of 35 knts. Most of the intensities on July 31 remain unchanged. At 18z, the intensity is elevated to 45 knts based on a Data-T number of T3.0/45 knts. At 0z and 6z, a shear matrix supported T3.0/45 knts so the intensity early on August 1 remains 45 knts. At 12z August 1, a FT of T3.5/55 knts supported winds of 55 knts, and a 18z DT of T4.0/65 knts supported 65 knts. A 21z DT of T4.5/77 knts supports 75 knts, but convection decreases thereafter, thus the 0z winds are set at 70 knts. However at 6z, DT and PT are T4.5/77 knts, so the intensity is then raised to 75 knts. An eye forms at 18z, so the intensity is increased to 80 knts then. Convection then diminishing slightly, so the intensity is held steady for 6 hours. Convection cools again at 12z, but DT's do not change, so 80 knts seems like a good estimate still. At 0600 UTC August 4, DT yields 5.0/90 knts, but a WMG eye is present, so 95 knts seems like a good peak intensity. The weakening portion of its life cycle is not changed.

Hurricane IsisEdit

August 5 18z, intensity is increased to 35 knt based on DT of 2.5. at 0z, the intensity is increased to 40 due a DT of 3.0 despite weak convection. T-numbers increase to T3.5 at 6z and 12z, but the intensity is set at 45 knots since due to the presence of dry air, which could have limited surface mixing. At 18z, the intensity is increased to 50 knots following an increase in organization. A burst of deep convection occurs at 0z August 7, so the intensity is changed to 55 knots then. Twelve hours later, Isis is believed to have become a hurricane based on a DT of 4.0. Dry air served as a limiter to the storm's intensity thereafter, but DT ranged from 4.0 to 4.5 through early August 8. At 1200 UTc, the colder cloud tops begin to wrap around the center, resulting in a DT of 5.0/90 knts. Due to it's ragged appearance, 85 knts is a good estimate of the intensity at this time, but the eye warm at 18z, so a 90 knot intensity is used then. The rest o the storm's life is not changed.

Hurricane KayEdit

Genesis pushed back 6 hours to 0z September 16. At 6z, intensity is at 35 knts due to a DT of T2.5. A bursting CDO pattern develops, and the 12z estimate of 45 knts is conservative, but based on DT=3.0/45 knts. Early on September 17th, the intensity is increased to 55 knots based on a DT of 3.5. At 6z September 17, DT equals T4.0/65 knts, so Kay is upgraded into a hurricane. An eye develops at 12z on IR, so DT is estimated to be at T4.5/77 knts (T5.0 if the eye wasn't elongated), but due to a partial ring of -75C cloud tops, 80 knts is selected as the intensity. DT reaches T5.5/102 knts at 18z, but due to a very cold (-50Cish) eye, 95 knts is chosen as the intensity. At 0z September 18, DT reaches T6.5/127 knts, with an OW eye (likely around -20C) surrounded by CMG (and some spots of CDG), with a eye number (W ring) of 6.0 and a . eye adjustment. However, constrains are limited to T6.0/115 knts, and 115 knots seems like a good estimate, but might be too bullish due to a cool eye. at 6z September 18, DT falls to T5.5 as the eye becomes obscured, so the intensity ls held at 115 knts for 12 more hours. Weakening is observed later on , and the 18z intensity is cut to 110 knts and is lowered further to 95 knots at 0z. DT is at 5.0 at 6z and 12z, so 90 knots is a good estimate then. Intensities thereafter are reduced further to account for more weakening than the EPHC estimated. An eye tries to re-form at 12z September 21, so 60 knots seems like a good estimate then, slightly above DT of 3.5/55 knts using both a curved band and eye pattern. DT reaches T5.0/90 knts at 18z, but due to uncertainties and constraints (making FT T4.5), 70 knts is a good estimate. A dry slot prevents further deepening overnight. By 18z September 22, DT once again becomes T4.0/65 knts, but only due to a small dry slot north of the core, so 70 knt is a good estimate then, based on improved organization since 12z. At 0z, a WMG re-develops, and DT is increased to T5.5, with +.5 eye adjustment. Due to the lopsided nature of the storm, and slightly ragged eye, 90 knts seem like a good intensity. Cold cloud tops briefly re-from around the eye at 0z, but cloud tops warm thereafter, and DT falls to T5.0, but enough to keep the intensity at 90 knots. DT falls to T4.5 at 12z, so the intensity is soon lowered to 80 knots. DT increased to 5.0, but PT is 4.5 at 0z, so 85 knt is chosen as the intensity estimate. This was short-lived as DT soon falls back to T4.5, and thus, the intensity is slowly lowered, and DT falls to T4.,0 briefly. At 0z, DT returns to T5.0, but since it seemed to flare up at around 0z only, 75 knts is a good estimate. At midday September 26, the intensity is cut to 65 knts based on a DT of 4.0. The reminded of Kay's life the intensity is mostly unchanged.

1981Edit

Hurricane FernandaEdit

On August 6 at 12z, the EPHC declared what would become Fernanda a depression. However, this was likely declared too late, based on DT of 3.0 (arguably 2.5), and thus, genesis is pushed back 12 hours and at 12z, the intensity is conservatively assigned at 40 knots and this could be conservative. At 1800 UTC, a CDO develops, so the intensity is raised to 45 knts despite diminished banding. At 0z August 7, DT reaches T3.5, so 55 knots sounds like a good estimate. At 0600 UTC, DT reaches 4.0, but since the banding remains unchanged, the winds are set at 60 knots. At 1800 UTC, DT remains 4.0 and due to increase organization, Fernanda is then classified as a 65 knot hurricane. Increased wind shear then taks a toll on the system, as DT falls to 3.5 12 hours later, and thus the intensity is brought down to 60 knots at 0z when convection decreases and 55 knots at 6z. At 12z, DT is 4.0 using a CDO pattern, T3.5 using a shear pattern, and T3.0 using curbd band. As a blend, the intensity is retained at 55 knots. At 18z, DT is a borderline T3.5-T4.0, so the intensity is elevated to 60 knots. DT is a solid 4.0 at 0000 UTC August 9, so the intensity is increased to 65 knots. Six hours later, DT reaches 4.5, so the intensity is set at 75 knts. At 12z, DT reaches 5.0 and remains at 5.0 at 18z, so the intensity for both packages is set at 90 knots. At 0z, DT remains 5.0 largely due to a slightly incomplete B ring, but given the eye warming, the intensity is upped to 95 knots, which is reasonable given that at 3z, DT reaches 5.5. At 6z August 10, DT is again T5.5/102 knts, so 100 knots is used as the intensity.

At midday August 10, DT reaches T6.0/115 knts but PT is at T5.5/102 knts (a case could be made for a PT of T6.0 though). While cloud tops are not as cold as I'd like, the system is very symmetrical and the eye is likely around +14C and very circular. This corresponds to an intensity of 115 knots. At 18z, a pair of Dvorak fixes yielded T6.0/115 knts, so the intensity then remains 115 knots. At 0z August 11, a pair of fixes yield T-numbers of 5.55 and 6.0, but given that the CI values are 6.0 (that 5.5 DT assumes no add for BF due to MET of 5.5) and the little overall change in presentation, 115 knts is once again the intensity estimate. Fixes at 3z supported a DT of 5.0 while a DT fixes yielded T3.5 with shear pattern and T4.5 with CDO pattern. Owing to lag, higher CI values, constraints, as well the fact when transiting to a banding pattern, the presentation can be downright ugly, even though Reconnaissance Aircraft data form Isabel to Iselle suggests otherwise. 95 knts here is the selected intensity. For the above reasons, slight adjustments are made for the rest of Fernanda's life cycle.

Hurricane NormaEdit

Based on DT of 2.5 at 18z October 8 and DT of 3.0 six hours later, genesis pushed back 12 hours and intensity at 18z and 0z set to 35 and 45 knts respectively. At 0600 UTC September 9, the intensity is increased to 55 knots based on DT of 3.5. At 1200 UTC, DT is set at 4.0, and the intensity is reluctantly increased to 65 knts, despite constraints. Two Dvorak fixes at 15z supported DT's of 5.0 and 5.5, but FT is limited to T3.5 due to constraints. An 18z fix had a DT of 5.0, but limited to T4.5 due to constraints. Given the ragged structure and open eyewall, 80 knts is chosen as the intensity at 18z. T-numbers are at 5.0 (breaking constraints due to high FT and the fact sufficient time has taken place for the presentation to catch up) at 21z, and a pair of fixes at 0z support T5.5 and T6.0 respectively. A blend of the above estimates, along with a rapidly cooling CDO and a OW (around -5C likely) eye support an intensity of 105 knots. Fixes at 3z and two at 6z support a DT of T6.5/127 knts. However, due to lag and a somewhat cool eye, 120 knts is the 6z intensity. Two fixes at 9z gave it a DT of 6.5 and 6.0 (due to the thining of convection) while a 10z fix using IR gave it a 6.5 while the VIS one got T6.0. A 12z fix also gave it a DT of 6.0. Normally these estimate correspond with keeping the intensity as it, but due to the warming of the eye, 125 knts is a good estimate. DT stays 6.0 at 15z and 18z, but due to warming cloud tops, the intensity is reduced to 115 knots. At 21z, the eye warms to WMG but barely and DT returns to T6.5, but PT is at T6.0 along with MET. This was short-lied as two fixes at 0z are at T6.0. 115 knts is a good estimate at 0z, given the warming cloud tops. A pair of fixes at 3z support DT's of T5.0 and T5.5. At 6z, DT falls to T4.5 as the eye collapses. CI values are higher, around 5.5, so 100 knts seems like an ok estimate. The eye does not come back, and as DT stays at T4.5 at 9z and 12z, it is assumed the winds catch up. 85 knts is a good estimate at 12z and a little below a CI value of T5.0. At 15z, the CDO becomes more defined, and DT is again T5.0 with PT of T5.5. DT's remain unchanged at 18z, but falls to 4.5 at 21z despite little change in organization and convection, even though it is evident wind shear is on the rise. DT returns to 5.0 at 0z, so 90 knts is still a good estimate. An eye re-forms in IR at 3z, and thus DT at the time from two separate fixes are 4.5 and 5.5. At 6z, DT ranges from 5.0 to 6.0. FT in the instance would be 5.0 and 5.5. At 6z October 12, 95 knts seems like a good intensity. At 9z and 12z, FT and DT are a consistent T5.5/102 knts (possible +.5 eye adjustment though not factor in to avoid inflating DT). A 10z fix gave a DT of 6.0 with B ring, .5 eye adjustment, but DT there could also be 6.5 if the you give it a W ring. PT at 10z is also 6.0 while MET is 5.5 Given the dramatic improvement from 6z to 10z and uncertainty in the DT and FT, 105 knts seems like a good estimate at 12z, ableit due to the apparent significant warming in cloud tops between 10z and 12z and possible lag up or down. Center fix also moved offshore at 12z. Landfall pushed back and an inland decay rate assumed along with extrapolation.Landfalls are to be looked at more in depth at a later date.

1982Edit

Hurricane DanielEdit

Genesis start time for this is reasonable and doesn't need to be pushed back. 25 knts is likely good for its initial intensity. At 6z, intensity increased to 35 knts based on FT of T2.5. Midday on July 7, DT reaches T3.0, so 45 knts is the intensity at that time. Fixes at 15z and 18z support T3.0/45 knts and T3.5/55 knts. An intensity of 50 knts is derived by blending the data. Four Dvorak fixes were made during the next six hours agree on a T3.5. Given the improved organization, the intensity at 0000 UTC July 8 is set at 55 knots. Data T-number at 3z and 6z increase to 65 knts, so Daniel is upgraded into a hurricane at 0600 UTC. Six hours later, Dvorak fixes remain unchanged, but PT is at 4.5, so the intensity is upped to 70 knts at that time, even though cloud tops start to warm after 10z. Convection decreases further at 18z, so the 70 knot intensity is likely generous. A partial CDO starts to come back, and at 21z, DT is 4.5 using CDO pattern and 4.0 using curved band. At 22z and 0z, DT increases to T4.5 using a cured band, so 75 knts is the intensity used at the time. Little change in intensity is noted throughout the day. Outflow becomes lees defined at 18z, evident that moderate wind shear affected the system at that time, and thus the cloud pattern deteriorates slightly. In accordance with Dvorak rules, the intensity; however, is held at 75 knts throughout the day. At 0z July 10, Daniel becomes more organized, and PT reaches 5.0 even though DT is at 4.5 using a curved band pattern. A fix at 3z and another at 6z had a DT of 4.5 using a CDO pattern, but with a curved band pattern, one gets a DT of 4.0 or 4.5. The intensity is actually lowered to 70 knts based on once again a slighlty sheared nature. At 12z, the intensity is held at 70 knts based on little structural change. At 18z, a more confident DT of T4.5 supports raising the winds back to 75 knts. At 22z, DT is at 6.5 (W eye no and +0.5 eye adjustment) while two hours later, two separate fixes go with a DT of T5.0, likely due to the pinhole eye. An intensity of 95 knts is selected based on a conseratie blend of the three data at 0z. A pinhole eye rapidly clears out thereafter, and a previous 21z gets an FT of T6.0, but a 0z fixes gets a T5.0. Given Dvorak's longtime troubles with pinhole eye storms, 105 is a good estimate but after the CDO becomes more symmetrical, a 10z fix gets a DT of T6.5. A 12z fix gets a T5.5 but the res is not very good and is ignored due to the pinhole eye structure. 120 knts seems like a good estimate here at 12z. A 15z fix has a DT of T6.5, but a 18z, this number falls to T5.5 as the western convection erodes. Given that there may be some lag in weakening, the intensity remains 120 knts based on high CI values. By 0000 UTC July 12, DT is diminished to T5.0 (higher if you add for BF), but the eye is warming, so the intensity is set at 110 knts. Six hours later, the DT skyrockets to a T6.5 (arguably T7.0 or T6.0), but due to its asymmetry, the intensity is only at 120 knots. At 12z and 15z, DT is 6.0 and the intensity is as such set at 115 knts due to warm cloud tops, but due to the presumed 18C+ eye, this could be too low. At 18z, two separate fixes get a DT of 6.0 and 6.5. Based on the blend of the T numbers and the cooling cloud tops and better organization, the intensity is increased to 120 knots. At 0000 UTc on July 13, most of the -0C (b) vanishes, and thus the intensity is lowered to 110 knts, which is still a bit above the DT of 5.5. At 3s and 6z, DT falls to 5.0, but mostly due to the warming of the CDO. Owing to higher CI intensities, 100 knts seems like a good estimate at 6z.

Hurricane GilmaEdit

Based on impressive CDO pattern, genesis is pushed back 12 hours. At the time of original genesis (0600 UTC July 26), intensity is estimate to be at 40 knts, based on two separate fixes of T2.5 and T3.0. Little change in organization is noted over the next 12 hours, so the 12z is kept at 40 knts. At 15z and 18z, DT is 3.0; the 18z intensity is set at 45 knts at 18z, and then 50 knts based on the consolidation of a nice CDO. At 6z, the intensity remains 50 knts based on EPHC estimates. DT reaches a borderline T3.5/55 knts at 15z, so the intensity is increased to such around that time. By 0000 UTC July 8, FT reaches 4.0, Six hours, DT is 4.5 using a CDO pattern, so the intensity is conservatively set at 75 knts then. DT is held at T4.5 at 12z, so the intensity remains unchanged at that time. At 18z, the storm becomes better organized and banding increases, but DT is still 4.5, so the intensity is increased only slightly to 80 knots. An eye clears and a 0000 UTC July 29, DT reaches 5.0/90 knts with an eye pattern (4.5 embedded in MG, B surrounding OW is +5 eye adjustment). The intensity at this time is set at 90 knots, but this could be conservative, given that DT at 2328z and DT at nother fix at 0z were set at 5.5 with a .05 eye adjustment. At 0600 UTC July 29, DT reaches 6.5, with another two fiesx three hours earlier suggesting a DT of 6.0 and 6.5. 110 knts is used as the intensity as this time as we assume the wind field has yet to catch up with the satellite signature. Two fixes at 9z and two more at 12z supported DT's of 6.0, 6.0, 6.5, and 6.5. Thus, the intensity is increased to 120 knts at 12z. After 12z, cloud tops start warming fast, and DT falls to 5.5 by 18z. Intneisty as such is lowered to 110 knts. Rest of Gilma's lifecycle is mostly unchanged.

Hurricane JohnEdit

Midday August 2, the EPHC upped an area of disturbed weather to a tropical depression. Development was slow to occur, as the intensity is set at 30 knts at genesis time. Convective activity soon diminishes, so little change in strength is shown during that time. At 0000 August 4, DT reaches T2.5, so the system is belied to have attained tropical storm threshold at that time. Later that day, DT briefly reaches 3.0, but banding decreases thereafter and convection is limited, so the intensity is set at 40 knts at 18z and 0z. Despite shallow convection, DT reaches 3.0 at 6z and 3.5 at 9z, so the intensity is revised upward respectively. An eye starts to become evident at 0z, when a T4.0 is attained via a CDO pattern, and thus the intensity is then increases to 65 knts. At 21z, an eye becomes evident, and at 23z, DT reaches 6.0 with a rapidly clearing OW eye. Cloud tops warm slightly thereafter, and 0z, DT falls to 5.5. Due to the shallowness of the convection, as well lag of the wind field, 85 knts is a good estimate. At 3z and 6z, DT remains 5.5, so the intensity is increased to 100 knts then. At 12z, DT returns to 6.0 with a fix at 1223z giving 6.5. Given that the eye appears to be positive, 120 knts is the selected intensity, which could be conservative. At 18z, DT falls to 6.0, but since the eye doesn't really cool the intensity is held at 120 knts. At 0z DT is 5.5 but CI is 6.5, so the intensity is set at 110 knts in between the two extremes. At 6z, DT from two fixes are 5.5 and 6.0, so the intensity is brought down to 105 knts. At 11z, DT is still 5.5 but likely due to sat resolution differences, DT is lowered to 5.0 with a CI values of 5.5. At this time, the intensity is cut to 100 knots. At 15z and 18z, DT stabilizes at 5.5, so the intensity is kept at 100 knots. The rest of John's lifecycle remains unchanged for the most part.

Hurricane OliviaEdit

Olivia's evolution was very typical of an EPAC hurricane. Genesis began at 1200 UTC September 18 (six hour earlier than operational EPHC esimtates) with winds of 30 knts in agreement with DT. PT reaches 3.0 six hours later and Dt is also at 3.0, but due to lag, 40 knts is the intensity at 0z September 19. At 6z, DT is split between 3.0 and 3.5 and a CDO forms, so 50 knts is set as an estimate, but this could be conservative. At 12z, the presentation warrants a T3.5/55 knts from one fix and a T4.0/65 knts from another. Even when factoring in lag with these kinds of systems, 55 knts is still justifiable given the potent CDO. A fix at 15z and another 18z got a T4.0, so Olivia is estimated to have reached hurricane intensity. At 21z 0z and 3z, three fixes were done, giving this is a 4.0, 4.0, and 4.5 respectively. Given that an eye is starting to show in late VIS imagery on September 19, the intensity is upped to 70 knts at 0z. Six hours later, DT reaches 4.5 as an eye starts to clear. Thus, the intensity is increased to 75 knts at 6z. A 10z fix gave a DT of 5.0 but a 12z fix gave a DT of 4.5 (close to 5.0 though there); both these fixes were attained through a CDO pattern. As a compromise, 80 knts is the intensity assigned at 1200 UTC September 20. Two fixes at 15z give intensites of 5.5 but another fix at 18z gave a T6.0. Due to lag, the intensity at 18z is set at 100 knts. DT at 21z is 6.5, but DT at 20z and 0z is 7.0. Six hour DT avg is 6.8, which does justify breaking constraints for a FT of 7.0 at 0z. However, due to lag in winds, the intensity is only set at 120 knots. Three of the four fixes between 0z and 6z supported T7.0 with one at T6.. Still, due to questions about the eye temperature, the intensity is only increased to 130 knts. Cloud tops briefly warm after 6z, with 9z and 12z DT is a t 6.5, bot owing to higher CI values, the intensity remains 130 knots. At 18z, the eye is very questionable OW, which seems suspicious given the evolution and structure of Olivia which closely mirrored that of a Category 5 hurricane. DT without BF is 6.5 but with a +.5 BF, 7.0. A GOES 5 picture at 18z suggested that the storm did indeed have a straight forward DT of 7.0. Henceforth, the 18z intensity is tentatively increased to 140 knots. At 18z, T numbers fall to 6.5/7.0, so the intensity is cut to 135 knts, given that the eye is still quite warm.

Hurricane PaulEdit

Hurricane IwaEdit

Gensis pushed back some due to initial DT of 3.0 at CPHC start time and per CPHC report. Original genesis time intensity is 45 knts, up from 40 knts. The T unmbers reaches 3.5 at 6z, so the system is estimated to hae attined winds of 50 knts then. The T number is also at 3.5 at 12z, so the intensity then is at 55 knts. For a while, the storm becomes tough to classify via the Dvorak Technique. Shear seemed to take toll on it, so the intensity is briefly lowered. At 18z on the 21st, DT is confirmed T3.5, so the intensity is brought back to 55 knts. DT reaches T4.0 at 0z so Iwa is believed to have become a hurricane at this time. Two fixes both yield a DT of 4.5 at z using a cured band pattern, so 75 knts is the given estimate at this time. An eye becomes visilbe at 12z, so Iwa likely was 80 knots at that time. However, increased outflow overides the eye, so the next three fixes are done via CDO pattern. At 18z, the system likely attained winds of 90 knots. Dvorak estimate remain unchanged as Iwa struggles to clear out an eye, perhaps due to wind shear. Reconnaissance data arrived at 18z on the 23rd, so no real changed are made thereafter. Intensity on approach, however, is upped to 85 knts based on per MWL, 120 mph wind gusts on Uhau and Kaui, south of the likely smallest winds. This would support an intensity of around 100 knots, but due to uncertainties of the altitude of this, the intensity is set at 85 knts, which is still 15 knots above Recon.

1983Edit

1984Edit

1985Edit

1986Edit

1987Edit

1988Edit

1989Edit

1990Edit

1991Edit

1992Edit

1993Edit

1994Edit

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