EPAC: GREG - Tropical Depression

[Cyclenall]

I'm thinking this will ultimately become a major hurricane.

Yeah why not, all the hurricanes in the Epac this year so far that has been in a similar area and track projection seem to all make it despite model guidance and just regular guidance in general. My gut feeling on this was no for MH strength but that gut has been wrong half the time .

MH seems likely IMO.

You called Eugene perfectly so lets see how this one acts.

[Kingarabian]

We have Greg.

000
WTPZ42 KNHC 170833
TCDEP2

TROPICAL STORM GREG DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL EP072011
200 AM PDT WED AUG 17 2011

DEEP CONVECTION ASSOCIATED WITH THE DEPRESSION HAS BEEN INCREASING
IN INTENSITY AND COVERAGE DURING THE PAST SEVERAL HOURS. SATELLITE
INTENSITY ESTIMATES ARE A UNANIMOUS 35 KT FROM ALL AGENCIES AT 0600
UTC. IN ADDITION...A SHIP REPORTED WINDS OF 35 KT JUST TO THE NORTH
OF THE ESTIMATED CENTER AT 0300 UTC. BASED ON THESE DATA...THE
INITIAL WIND SPEED IS INCREASED TO 35 KT...WHICH MAKES THE CYCLONE
TROPICAL STORM GREG.

THE LOW-LEVEL CENTER OF GREG HAS BEEN DIFFICULT TO LOCATE...BUT
USING THE AFOREMENTIONED SHIP OBSERVATION IT APPEARS TO BE A LITTLE
TO THE NORTH OF THE PREVIOUS TRACK. THE TROPICAL STORM IS MOVING
WEST-NORTHWESTWARD AT 14 KT TO THE SOUTH OF A STRENGTHENING
MID-LEVEL HIGH CENTERED OVER THE SOUTHWESTERN UNITED STATES. A
SLIGHT TURN TOWARD THE LEFT WITH SOME INCREASE IN FORWARD SPEED IS
FORECAST DURING THE NEXT DAY OR SO AS GREG MOVES DIRECTLY SOUTH OF
THE HIGH. GLOBAL MODELS ARE IN AGREEMENT IN SHOWING THE RIDGE
WEAKENING ON FRIDAY DUE TO A TROUGH MOVING OVER THE U.S. WEST
COAST. THIS PATTERN SHOULD CAUSE THE CYCLONE TO SLOW DOWN IN THE
LONGER RANGE. THE NEW OFFICIAL FORECAST IS A LITTLE NORTH OF THE
PREVIOUS ONE FOR THE FIRST COUPLE OF DAYS AND THEN LIES VERY NEAR
THE PREVIOUS TRACK. THIS FORECAST IS A LITTLE FASTER AND TO THE
SOUTH OF THE MULTI-MODEL CONSENSUS...LEANING TOWARD THE GFS AND
ECMWF MODELS.

GREG IS CURRENTLY IN AN ENVIRONMENT OF MODERATE NORTHEASTERLY
SHEAR...SEA SURFACE TEMPERATURES OF ABOUT 30C...AND A RELATIVELY
MOIST ATMOSPHERE. DURING THE NEXT TWO TO THREE DAYS...THE SHEAR IS
EXPECTED TO SLACKEN AND SEA SURFACE TEMPERATURES ALONG THE FORECAST
TRACK GRADUALLY LOWER BUT REMAIN ABOVE 26C. THESE CONDITIONS
SUPPORT INTENSIFICATION...AND THE OFFICIAL FORECAST IS AT THE HIGH
END OF THE GUIDANCE DURING THIS PERIOD. GREG IS EXPECTED TO MOVE
OVER SUB 26C WATERS AND INTO A MORE STABLE ATMOSPHERE IN ABOUT
THREE DAYS...AND THAT SHOULD INDUCE A STEADY WEAKENING TREND.

[cycloneye]

TROPICAL STORM GREG DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL EP072011
800 AM PDT WED AUG 17 2011

SATELLITE IMAGERY INDICATES THAT GREG HAS STRENGTHENED THIS MORNING
AS A CENTRAL DENSE OVERCAST HAS DEVELOPED WITH AN OUTER CONVECTIVE
BAND OVER THE NORTHWESTERN SEMICIRCLE. SATELLITE INTENSITY
ESTIMATES ARE 55 KT FROM TAFB AND 35 KT FROM SAB...SO THE INITIAL
INTENSITY IS INCREASED TO 45 KT. ANALYSES FROM CIMSS AT THE
UNIVERSITY OF WISCONSIN SHOW 10-15 KT OF NORTHEASTERLY VERTICAL
WIND SHEAR STILL AFFECTING THE STORM...AND RECENT MICROWAVE DATA
SUPPORTS THIS BY SHOWING A SOMEWHAT SHEARED PATTERN TO THE
CONVECTION UNDERNEATH THE CDO.

THE INITIAL MOTION IS NOW 300/18...WHICH IS FASTER THAN BEFORE.
GREG IS LOCATED BETWEEN A LARGE MID/UPPER-LEVEL RIDGE OVER THE
SOUTHERN UNITED STATES AND NORTHERN MEXICO AND A LARGE BUT WEAK
TROPICAL DISTURBANCE TO ITS WEST AND SOUTHWEST. DURING THE NEXT
COUPLE OF DAYS...THE DISTURBANCE IS FORECAST TO WEAKEN DUE TO ITS
PROXIMITY TO GREG...LEAVING THE RIDGE TO THE NORTH AS THE MAIN
STEERING MECHANISM. THIS EVOLUTION SHOULD STEER THE STORM QUICKLY
TOWARD THE WEST-NORTHWEST FOR 24 HR OR SO...FOLLOWED BY A GRADUAL
TURN TOWARD THE WEST AND A DECREASE IN FORWARD SPEED. THE TRACK
GUIDANCE FOLLOWS THIS SCENARIO...ALTHOUGH THERE HAS BEEN A
NORTHWARD SHIFT LIKELY DUE TO THE INITIAL POSITION AND MOTION. THE
NEW FORECAST TRACK IS FASTER THAN AND A LITTLE TO THE NORTH OF THE
PREVIOUS FORECAST...AND IT LIES CLOSE TO THE VARIOUS CONSENSUS
MODELS.

THE FORECAST TRAVCK KEEPS GREG OVER SEA SURFACE TEMPERATURES OF 27C
OR WARMER FOR 36 HR...AND THE DYNAMICAL MODELS FORECAST THE SHEAR
TO DECREASE DURING THIS TIME. THIS COMBINATION SHOULD ALLOW
CONTINUED STRENGTHENING...AND THE NEW INTENSITY FORECAST CALLS FOR
A PEAK INTENSITY OF 75 KT IN 36 HR AS A BLEND BETWEEN THE SHIPS AND
LGEM MODELS. AFTER 48 HR...THE WATERS GET COOLER ON THE FORECAST
TRACK...WHICH SHOULD INDUCE A STEADY WEAKENING TREND.

FORECAST POSITIONS AND MAX WINDS

INIT 17/1500Z 16.7N 104.2W 45 KT 50 MPH
12H 18/0000Z 17.7N 106.6W 55 KT 65 MPH
24H 18/1200Z 18.4N 109.4W 65 KT 75 MPH
36H 19/0000Z 19.0N 111.8W 75 KT 85 MPH
48H 19/1200Z 19.4N 113.6W 75 KT 85 MPH
72H 20/1200Z 20.0N 116.5W 65 KT 75 MPH
96H 21/1200Z 20.5N 119.0W 45 KT 50 MPH
120H 22/1200Z 20.5N 122.0W 30 KT 35 MPH

$$
FORECASTER BEVEN

[Extratropical94]

Dvorak supports hurricane intensity:
17/1745 UTC 16.7N 106.0W T3.5/3.5 GREG -- East Pacific
Best Track does not:
18Z BT: EP, 07, 2011081718, , BEST, 0, 168N, 1056W, 55, 994, TS

[RL3AO]

Probably a cane within 12 hours.

[cycloneye]

TROPICAL STORM GREG DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL EP072011
200 PM PDT WED AUG 17 2011

GREG CONTINUES TO STRENGTHEN THIS AFTERNOON...WITH SATELLITE IMAGERY
SHOWING A CENTRAL DENSE OVERCAST WITH WELL-DEFINED OUTER BANDING IN
ALL QUADRANTS EXCEPT THE NORTHEAST. THERE HAS BEEN AN OCCASIONAL
DIMPLE IN THE CDO THAT MIGHT BE A FORMATIVE EYE. HOWEVER...THERE
IS NO RECENT MICROWAVE IMAGERY TO CONFIRM THE DEVELOPMENT OF AN
EYEWALL. SATELLITE INTENSITY ESTIMATES ARE 55 KT FROM TAFB AND
SAB...AND THAT IS THE INITIAL INTENSITY. THE CIRRUS OUTFLOW IS
GOOD IN THE WESTERN SEMICIRCLE AND POOR IN THE EASTERN SEMICIRCLE.

THE INITIAL MOTION IS 290/20. GREG IS LOCATED BETWEEN A LARGE
MID/UPPER-LEVEL RIDGE OVER THE SOUTHERN UNITED STATES AND NORTHERN
MEXICO AND A LARGE BUT WEAK TROPICAL DISTURBANCE TO ITS WEST AND
SOUTHWEST. THIS DISTURBANCE SHOULD SLOWLY WEAKEN DUE TO ITS
PROXIMITY TO GREG...LEAVING THE RIDGE TO THE NORTH AS THE MAIN
STEERING MECHANISM. THIS EVOLUTION SHOULD STEER THE STORM QUICKLY
TOWARD THE WEST-NORTHWEST FOR 24 HR OR SO...FOLLOWED BY A GRADUAL
TURN TOWARD THE WEST AND A DECREASE IN FORWARD SPEED. WHILE THE
GLOBAL MODELS AGREE WITH THIS SCENARIO... MOST OF THEM HAD TOO WEAK
OF AN INITIALIZATION OF GREG AND SEEM TO BE TURNING THE STORM TOO
QUICKLY WESTWARD INTO THE DISTURBANCE. THE MODEL WITH THE BEST
INITIAL REPRESENTATION OF GREG...NOGAPS...FORECASTS A TRACK NEAR
THE NORTH EDGE OF THE GUIDANCE ENVELOPE. OVERALL...THE TRACK
GUIDANCE HAS SHIFTED SIGNIFICANTLY SOUTHWARD FROM THE PREVIOUS
ADVISORY. THE NEW FORECAST TRACK WILL ALSO SHIFT A LITTLE TO THE
SOUTH. HOWEVER...IT LIES ON THE RIGHT SIDE OF THE GUIDANCE
ENVELOPE BETWEEN THE NOGAPS AND THE CONSENSUS MODELS.

THE FORECAST TRACK KEEPS GREG OVER SEA SURFACE TEMPERATURES OF 27C
OR WARMER FOR 24-36 HR...AND THE DYNAMICAL MODELS FORECAST LIGHT
VERTICAL WIND SHEAR DURING THIS TIME. THIS COMBINATION SHOULD
ALLOW CONTINUED STRENGTHENING...AND THE NEW INTENSITY FORECAST
CALLS FOR A PEAK INTENSITY OF 80 KT IN 36 HR AS A BLEND BETWEEN THE
SHIPS AND LGEM MODELS. AFTER 36 HR...THE WATERS GET COOLER ON THE
FORECAST TRACK...WHICH SHOULD INDUCE A STEADY WEAKENING TREND. THE
RAPID INTENSIFICATION INDEX OF THE SHIPS MODEL SHOWS A 40 PERCENT
CHANCE OF A 25 KT INTENSIFICATION DURING THE NEXT 24 HR AND A 20
PERCENT CHANCE OF A 40 KT INTENSIFICATION. THUS...IT CANNOT BE
RULED OUT THAT GREG COULD GET MUCH STRONGER THAN CURRENTLY
FORECAST.


FORECAST POSITIONS AND MAX WINDS

INIT 17/2100Z 17.1N 106.5W 55 KT 65 MPH
12H 18/0600Z 17.9N 109.0W 65 KT 75 MPH
24H 18/1800Z 18.5N 111.8W 75 KT 85 MPH
36H 19/0600Z 18.9N 113.9W 80 KT 90 MPH
48H 19/1800Z 19.2N 115.6W 75 KT 85 MPH
72H 20/1800Z 19.5N 118.5W 60 KT 70 MPH
96H 21/1800Z 20.0N 121.5W 40 KT 45 MPH
120H 22/1800Z 20.0N 123.5W 25 KT 30 MPH

$$
FORECASTER BEVEN

[RL3AO]

Greg can see.

[RL3AO]

Microwave to confirm.

[KWT]

Yet another EPAC system that seemingly has no trouble in forming...

Looks like this season may well be heading towards above average ACE at the least...

[CrazyC83]

18/0000 UTC 17.3N 107.4W T3.5/3.5 GREG -- East Pacific

[CrazyC83]

Based on latest Dvorak estimates and the looks, I would go 60 kt right now. No agency can confirm a hurricane yet, but it is mighty close.

[RL3AO]

BEST TRACK: EP07, 173N 1075W, 65kts, 987mb, HU GREG

[Yellow Evan]

Looks like we have another hurricane.

[cycloneye]

HURRICANE GREG DISCUSSION NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL EP072011
800 PM PDT WED AUG 17 2011

LATE AFTERNOON VISIBLE SATELLITE IMAGES SHOWED A BANDING EYE
FEATURE THAT BECAME OBSCURED AS NEW CONVECTION DEVELOPED NEAR
THE CENTER AROUND SUNSET. THE SMALL EYE FEATURE WAS ALSO EVIDENT
IN A 2025 UTC TRMM OVERPASS. UNFORTUNATELY...THERE HAS BEEN NO
ADDITIONAL MICROWAVE IMAGERY SINCE THAT TIME. ALTHOUGH DVORAK FINAL
T-NUMBERS FROM TAFB AND SAB WERE 4.0 AND 3.5...RESPECTIVELY...THE
DATA T-NUMBERS FROM BOTH AGENCIES WERE 4.0. THIS SUPPORTS
INCREASING THE WIND SPEED TO 65 KT. GREG BECOMES THE SIXTH
HURRICANE IN THE EASTERN PACIFIC BASIN IN 2011.

SEA SURFACE TEMPERATURES ALONG THE PATH OF GREG GRADUALLY COOL
THROUGHOUT THE FORECAST PERIOD...HOWEVER THE CYCLONE IS FORECAST
TO REMAIN OVER 27-28 DEGREE CELSIUS WATER FOR ANOTHER 24 HOURS OR
SO. DURING THAT TIME...SHEAR IS EXPECTED TO REMAIN LIGHT WHICH
SHOULD ALLOW FOR ADDITIONAL STRENGTHENING. THE UPDATED FORECAST
INDICATES A PEAK INTENSITY OF 85 KT IN 24 HOURS AND IS IN BEST
AGREEMENT WITH THE SHIPS/LGEM GUIDANCE. THEREAFTER...STEADY
WEAKENING IS SHOWN AS GREG IS FORECAST TO MOVE OVER DECREASING
SSTS.

THE INITIAL MOTION REMAINS A BRISK 285/19. GREG CONTINUES TO BE
STEERED QUICKLY WEST-NORTHWESTWARD BETWEEN A LARGE MID/UPPER-LEVEL
RIDGE OVER THE SOUTHERN UNITED STATES AND A CYCLONIC GYRE TO THE
SOUTHWEST OF THE CYCLONE. AS THE GYRE WEAKENS DURING THE NEXT 24
HOURS...GREG SHOULD TURN WESTWARD AND SLOW DOWN. THE WESTERN
PORTION OF THE RIDGE IS FORECAST TO WEAKEN IN A COUPLE OF DAYS AS A
TROUGH APPROACHES THE WEST COAST OF THE UNITED STATES. THIS SHOULD
RESULT IN A FURTHER REDUCTION OF FORWARD SPEED. THE MODELS ARE IN
GOOD AGREEMENT ON THIS SCENARIO...BUT THE LATEST GUIDANCE ENVELOPE
HAS SHIFTED SOUTHWARD AT 72 HOURS AND BEYOND. THIS REQUIRES A
SOUTHWARD ADJUSTMENT TO THE TRACK IN THE LATTER PORTION OF THE
FORECAST PERIOD.


FORECAST POSITIONS AND MAX WINDS

INIT 18/0300Z 17.5N 108.3W 65 KT 75 MPH
12H 18/1200Z 18.1N 110.8W 75 KT 85 MPH
24H 19/0000Z 18.6N 113.4W 85 KT 100 MPH
36H 19/1200Z 18.9N 115.4W 75 KT 85 MPH
48H 20/0000Z 19.0N 117.5W 65 KT 75 MPH
72H 21/0000Z 19.0N 120.0W 50 KT 60 MPH
96H 22/0000Z 19.0N 122.5W 35 KT 40 MPH
120H 23/0000Z 19.0N 124.5W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
FORECASTER BROWN

[Battlebrick]

6/6!

Come on Fernanda!

[Kingarabian]

6/6!

Come on Fernanda!

She's trying!

[Yellow Evan]

On wheather or not the EPAC goes 7 for 7, it is all up to Fernanda. Let the TC decide. However, i'd become a cane if I were you Fernanda.

[Kingarabian]

18/0600 UTC 18.0N 109.3W T4.5/4.5 GREG -- East Pacific

[KWT]

Typically inm this area the NHC have somewhat under-estimated the strength of the systems...so I wouldn't rule out a major...

[Chacor]

That appears to be a really small microwave eye.