EPAC : TROPICAL DEPRESSION DARBY - DISCUSSION

[CrazyC83]

Looks like an impressive system...at this rate those calls for a weak EPAC season will bust quite badly, along with those super high Atl season...

Seems that way...although a fast start could flip once the Atlantic becomes more favorable. The main reason the EPAC is so strong right now is because the Atlantic is trying so hard but the conditions aren't good enough yet, so these waves and lows just sail into the Pacific where conditions are excellent.

[hurricaneCW]

We had all these systems within 10 days in the east pacific, we could easily see the same thing in the Atlantic once things get favorable. June means nothing in terms of overall tropical activity but if we don't see anything by mid July, than all those 18+ storm forecasts will likely bust.

[KWT]

Yeah I agree with you Crazy I think things will slow down once the Atlantic does kick in.

Wil lbe very interesting to see whether it can make it to category-4 like the NHC call, its presentation suggests it has a shot at least, probably 110-115kts range IMO until conditions start to cause weakening.

[HURAKAN]

Latest

[HURAKAN]

Latest

[Macrocane]

Yeah I agree with you Crazy I think things will slow down once the Atlantic does kick in.

Wil lbe very interesting to see whether it can make it to category-4 like the NHC call, its presentation suggests it has a shot at least, probably 110-115kts range IMO until conditions start to cause weakening.

This is Darby's thread, the one taht is forecaste to reach cat 4 is Celia

[cycloneye]

WTPZ45 KNHC 240239
TCDEP5
TROPICAL STORM DARBY DISCUSSION NUMBER 5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052010
800 PM PDT WED JUN 23 2010

THE RAPID INTENSIFICATION THAT DARBY WAS UNDERGOING EARLIER SEEMS TO
HAVE SLOWED OR STOPPED...AS THERE HAS BEEN NO RECENT HINT OF AN EYE
IN VISIBLE OR INFRARED IMAGERY AND MUCH OF THE OUTER BANDING
ASSOCIATED WITH DARBY HAS DISSIPATED. WHY THIS IS OCCURRING IS NOT
OBVIOUS...AS THERE ARE NO ANALYSES THAT SHOW SIGNIFICANT VERTICAL
WIND SHEAR AFFECTING THE STORM. IT IS POSSIBLE THAT EASTERLY
UPPER-LEVEL WINDS ARE UNDERCUTTING THE WELL-DEFINED ANTICYCLONIC
OUTFLOW. SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE 55
KT...AND THAT IS THE INITIAL INTENSITY FOR THIS ADVISORY.

THE INITIAL MOTION REMAINS 285/10. DARBY IS SOUTH OF A LOW/MID-
LEVEL RIDGE OVER MEXICO. THE LARGE-SCALE MODELS FORECAST THE RIDGE
TO WEAKEN AS A DISTURBANCE OVER THE NORTHWESTERN CARIBBEAN SEA
MOVES TOWARDS THE YUCATAN PENINSULA AND THE GULF OF MEXICO. THIS
SHOULD LEAVE DARBY IN AN AREA OF LIGHT STEERING CURRENTS BY 72-96
HR...WITH THE LOW-LEVEL FLOW TRYING TO MOVE THE CYCLONE EASTWARD
AND THE MID-LEVEL FLOW TRYING TO MOVE IT WESTWARD. THERE IS A
LARGE SPREAD IN THE DYNAMICAL MODELS AFTER 72 HR...WHICH IS ANOTHER
SIGN THAT THE CYCLONE IS LIKELY TO MOVE SLOWLY. THE NEW FORECAST
TRACK IS SIMILAR TO THE PREVIOUS TRACK...CALLING FOR A WEST-
NORTHWESTWARD MOTION AND DECELERATION FOR 48 HR OR SO...FOLLOWED BY
A NORTHWARD TURN AT A SLOW FORWARD SPEED. THE NEW TRACK IS IN BEST
AGREEMENT WITH THE FLORIDA STATE SUPERENSEMBLE.

DESPITE THE CURRENT TRENDS...THE INTENSITY GUIDANCE FORECASTS DARBY
TO STRENGTHEN FURTHER...WITH THE SHIPS AND LGEM MODELS SHOWING A
PEAK INTENSITY OF 80 KT IN ABOUT 48 HR AND THE SHIPS RAPID
INTENSIFICATION INDEX SHOWING A 40 PERCENT CHANCE OF 30 KT
STRENGTHENING DURING THE NEXT 24 HR. AFTER THAT...INCREASING
EASTERLY WIND SHEAR IS LIKELY TO ARREST DEVELOPMENT AND BEGIN A
WEAKENING TREND. THE NEW INTENSITY FORECAST FOLLOWS THE TREND OF
THE PREVIOUS FORECAST BUT AT SOMEWHAT LOWER INTENSITIES BASED ON
CURRENT TRENDS AND THE FORECAST SHEAR. THE NEW FORECAST IS
STRONGER THAN ALL THE GUIDANCE AT 96 AND 120 HR. IT SHOULD BE
NOTED THAT THE GFS...UKMET...NOGAPS...AND ECMWF MODELS SHOW DARBY
SHEARING APART AFTER 72 HR...WITH THE LOW-LEVEL CENTER MOVING
EASTWARD AND THE MID-LEVEL CENTER MOVING WESTWARD. SHOULD THIS
HAPPEN THE CYCLONE WOULD WEAKEN MUCH FASTER THAN CURRENTLY
FORECAST.


FORECAST POSITIONS AND MAX WINDS

INITIAL 24/0300Z 12.3N 97.0W 55 KT
12HR VT 24/1200Z 12.7N 98.3W 65 KT
24HR VT 25/0000Z 13.1N 99.8W 75 KT
36HR VT 25/1200Z 13.4N 100.9W 80 KT
48HR VT 26/0000Z 13.6N 101.7W 85 KT
72HR VT 27/0000Z 14.0N 102.5W 85 KT
96HR VT 28/0000Z 14.5N 102.5W 80 KT
120HR VT 29/0000Z 15.0N 102.5W 65 KT

$$
FORECASTER BEVEN

[KWT]

LOoks like we will get a June landfalling system on Mexico, very interesting to watch how this one evolves, looks very close to hurricane status now IMO.

[HURAKAN]

Latest

[brunota2003]

Nice eyewall...it is trying to cu!

[KWT]

Looks like a hurricane to me to be honest, very tight looking system which means it could ramp up a good deal more than expected if thats the case.

[cycloneye]

Still a TS at the 12z Best track.

EP, 05, 2010062412, , BEST, 0, 127N, 983W, 60, 994, TS

[HURAKAN]

24/1145 UTC 12.7N 98.3W T4.0/4.0 DARBY -- East Pacific

65 knots

[cycloneye]

Best track updated and now is a hurricane at 65kts.

EP, 05, 2010062412, , BEST, 0, 127N, 983W, 65, 990, HU

[Chacor]

Wouldn't be surprised if the NHC decided that in the three hours since the ATCF update Darby's reached hurricane strength.

EDIT: And wouldn't you know it, just as I say that, ATCF's updated to a hurricane.

[HURAKAN]

Latest

[Chacor]

Before Celia, the last June hurricane was Andres last year — but before that we hadn't had a June hurricane since 2000 with Carlotta. 2000 is also the last year we had two hurricanes by the end of June (Aletta had become a hurricane in May).

2000 had 17 named storms.

The last time two hurricanes have formed in the month of June was 1996, when Hurricanes Alma and Boris formed one after another in almost the same place. 1996 had 9 tropical storms, including an unnamed storm (One-E).

[HURAKAN]

Therefore, a fast start doesn't mean you will get a lot further!!!

[KWT]

Oh I don't think there can be any doubt that this is a hurricane right now, presentation not quite as good on the microwave but thats probably because of the Dmax causing stronger convection.

[cycloneye]

WTPZ45 KNHC 241436
TCDEP5
HURRICANE DARBY DISCUSSION NUMBER 7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052010
800 AM PDT THU JUN 24 2010

DARBY HAS A SMALL BUT SYMMETRIC CDO WITH SOME BANDING FEATURES OVER
THE WESTERN SEMICIRCLE. LATEST DVORAK INTENSITY ESTIMATES ARE 65
KT AND 55 KT FROM SAB AND TAFB RESPECTIVELY...AND DARBY IS BEING
UPGRADED TO A 65-KT HURRICANE AT THIS TIME. SINCE VERTICAL SHEAR
IS FORECAST TO REMAIN LIGHT FOR THE NEXT COUPLE OF DAYS...
ADDITIONAL STRENGTHENING SEEMS LIKELY. THE OFFICIAL INTENSITY
FORECAST IS ROUGHLY A BLEND OF THE SHIPS/LGEM AND GFDL MODEL
GUIDANCE. BY AROUND 72 HOURS...GLOBAL MODEL PREDICTIONS INDICATE
INCREASING SOUTHEASTERLY TO EASTERLY SHEAR OVER DARBY WHICH WOULD
INDUCE WEAKENING...AS SHOWN BY THE OFFICIAL FORECAST. HOWEVER
SINCE THE TROPICAL CYCLONE IS FORECAST TO REMAIN OVER SEA SURFACE
TEMPERATURES THAT ARE QUITE WARM THROUGH 5 DAYS...DARBY MIGHT NOT
WEAKEN AS MUCH AS SHOWN BY 4 AND 5 DAYS.

THE FORWARD SPEED IS SLOWING AND THE INITIAL MOTION IS NOW ESTIMATED
TO BE 285/8. THE LOW- TO MID-LEVEL RIDGE TO THE NORTH OF DARBY IS
FORECAST TO GRADUALLY WEAKEN SO A CONTINUED DECELERATION IS
EXPECTED OVER THE NEXT COUPLE OF DAYS. AFTER 36 HOURS...THE TRACK
GUIDANCE BECOMES QUITE DIVERSE SUGGESTING THAT THE STEERING
CURRENTS WILL BECOME VERY WEAK. BY DAYS 4-5...THERE IS STILL THE
POSSIBILITY OF SOME INTERACTION BETWEEN DARBY AND THE SYSTEM
CURRENTLY SITUATED OVER THE WESTERN CARIBBEAN. THIS WOULD BE MORE
LIKELY IF THE LATTER SYSTEM TAKES A MORE SOUTHERN TRACK AND
STRENGTHENS OVER THE BAY OF CAMPECHE BY AROUND 96 HOURS AS SHOWN IN
THE FORECAST FROM THE ECMWF GLOBAL MODEL. FOR THE TIME BEING THE
OFFICIAL TRACK FORECAST...LIKE THE PREVIOUS ONE...ONLY SHOWS A
NORTH TO NORTHEAST DRIFT OVER THE LAST 2 DAYS OF THE FORECAST
PERIOD.

FORECAST POSITIONS AND MAX WINDS

INITIAL 24/1500Z 12.8N 98.7W 65 KT
12HR VT 25/0000Z 13.0N 99.8W 70 KT
24HR VT 25/1200Z 13.3N 101.1W 75 KT
36HR VT 26/0000Z 13.5N 102.1W 80 KT
48HR VT 26/1200Z 13.7N 102.9W 80 KT
72HR VT 27/1200Z 14.0N 103.5W 70 KT
96HR VT 28/1200Z 14.5N 103.5W 65 KT
120HR VT 29/1200Z 15.0N 103.0W 55 KT

$$
FORECASTER PASCH