[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231101
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT 23 APR 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING
INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER
OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 1045 UTC.

...THE ITCZ...

ITCZ 7N11W 5N20W 1N30W...TO THE EQUATOR AT 34W...1S40W 1S45W.
SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND THUNDERSTORMS
ARE FROM 3N TO 4N BETWEEN THE PRIME MERIDIAN AND 2W...AND
SOUTH OF 4N TO THE EQUATOR BETWEEN 17W AND 36W. OTHER ISOLATED
MODERATE TO LOCALLY STRONG SHOWERS AND THUNDERSTORMS ARE FOUND
ELSEWHERE FROM THE EQUATOR TO 5N EAST OF 50W.

...DISCUSSION...

FROM THE EASTERN PACIFIC OCEAN TO THE GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL EASTERN PACIFIC OCEAN DIGGING TROUGH
RUNS FROM 37N124W TO 27N126W. AN UPPER LEVEL RIDGE...IN THE
EASTERN PACIFIC OCEAN YESTERDAY...NOW PASSES THROUGH 32N101W TO
22N102W 17N105W...THROUGHOUT THE INTERIOR OF MEXICO. UPPER LEVEL
NORTHWESTERLY WIND FLOW COVERS THE ENTIRE GULF OF MEXICO. THIS
NORTHWESTERLY WIND FLOW IS DIVING RAPIDLY INTO THE BASE OF AN
ATLANTIC OCEAN-TO-WEST CENTRAL CARIBBEAN SEA DEEP LAYER TROUGH.
A SURFACE COLD FRONT NOW RUNS THROUGH SOUTHEASTERN LOUISIANA
TO SOUTH CENTRAL TEXAS TO MEXICO JUST SOUTH OF THE TEXAS BIG
BEND. THIS FRONT IS FORECAST TO MOVE THROUGH THE ENTIRE GULF OF
MEXICO DURING THE NEXT 24 HOURS. SHOWERS AND THUNDERSTORMS ARE
IN A 20 TO 30 NM WIDE LINE FROM 29N85W IN THE NORTHEASTERN GULF
WATERS TO EASTERN GEORGIA. SURFACE RIDGE...NOT AS WELL DEFINED
AS THE RIDGE SIX HOURS AGO...FROM THE STRAITS OF FLORIDA INTO
THE SOUTH CENTRAL GULF TO THE WESTERN GULF OF MEXICO.

THE CARIBBEAN SEA...
STRONG SHOWERS AND THUNDERSTORMS ARE FOUND FROM 15N TO 18N
BETWEEN 64W AND 66W...EVERYTHING HAS SHIFTED A BIT EASTWARD...
AND APPEARS TO BE HEADING TOWARD THE LEEWARD ISLANDS JUST EAST
OF PUERTO RICO AND THE VIRGIN ISLANDS. SHOWERS ARE REACHING
PUERTO RICO AND ST.CROIX...WITH ST.CROIX BEING CLOSER TO THE
AREAS OF COMPARATIVELY STRONGER CONVECTIVE ACTIVITY THAN PUERTO
RICO. THIS STRONG CONVECTIVE ACTIVITY WITH THE SHOWERS AND
THUNDERSTORMS IS OCCURRING TO THE EAST OF A VORTICITY MAXIMUM
WHICH IS MOVING ACROSS SOUTHEASTERN PUERTO RICO AT THIS TIME.
THE GFS MODEL FOR 500 MB VORTICITY FOR 23/0600 UTC IS SHOWING
CORRECTLY THIS SCENARIO. THE MIDDLE TO UPPER LEVEL TROUGH WHICH
ALSO HAD BEEN FORECAST BY MODELS IS JUST TO THE WEST...FROM A
CYCLONIC CIRCULATION CENTER NEAR 31N70W TO 26N74W 21N75W...INTO
THE CARIBBEAN SEA NEAR 15N78W.  PRECIPITATION IS REACHING PUERTO
RICO AND THE VIRGIN ISLANDS EVEN THOUGH THESE TWO AREAS WEST OF
THE MOVED MOVING NORTH-NORTHEASTWARD...ABOUT 90 NM
SOUTH-SOUTHWEST OF PUERTO RICO. THIS IS PART OF THE RAIN
ACTIVITY WHICH THE SAN JUAN PUERTO RICO METEOROLOGISTS HAVE BEEN
FORECASTING TO DEVELOP AND REACH THEIR ISLAND...CAUSING HEAVY
RAINS AND POSSIBLE FLOODING AND MUDSLIDES DURING THE NEXT 48
HOURS. A DEEP LAYER TROUGH RUNS FROM A CYCLONIC CIRCULATION
CENTER NEAR 31N71W TO THE NORTHERN BAHAMAS NEAR 25N77W...ACROSS
CUBA AND JAMAICA...TO 15N80W IN THE WEST-CENTRAL CARIBBEAN SEA.
UPPER LEVEL SOUTHWESTERLY WIND FLOW IS MOVING OFF SOUTH AMERICA
INTO THE REST OF THE AREA...EAST OF THE DEEP LAYER TROUGH.
DISSIPATING SURFACE STATIONARY FRONT RUNS FROM THE ATLANTIC
OCEAN NEAR 32N39W TO 32N50W 30N56W 28N60W 20N68W...ACROSS THE
EASTERN PART OF THE DOMINICAN REPUBLIC TO 17N70W. THIS FRONT HAS
BEEN IN MORE OR LESS THIS SAME AREA FOR AT LEAST THE LAST WEEK.
UPPER LEVEL HIGH CLOUDS FROM THE SOUTHERLY FLOW FROM SOUTH
AMERICA COVER THE CARIBBEAN SEA EAST OF 70W.

THE ATLANTIC OCEAN...
A DEEP LAYER TROUGH RUNS FROM A CYCLONIC CIRCULATION CENTER NEAR
31N70W TO 26N74W 21N75W...INTO THE CARIBBEAN SEA NEAR 15N78W.
A DISSIPATING SURFACE STATIONARY FRONT RUNS FROM THE ATLANTIC
OCEAN THROUGH 24N64W TO 20N68W...ACROSS THE EASTERN PART OF THE
DOMINICAN REPUBLIC TO 17N70W. THIS FRONT HAS BEEN IN MORE OR
LESS THIS SAME AREA FOR AT LEAST THE LAST WEEK. BROKEN TO
OVERCAST MULTILAYERED CLOUDS AND POSSIBLE PRECIPITATION ARE
WITHIN 150 TO 200 NM ON EITHER SIDE OF 20N65W 24N64W 27N62W
30N56W 33N50W BEYOND 35N41W...AND FROM 24N TO 35N BETWEEN 20W
AND 40W. BROAD UPPER LEVEL ANTICYCLONIC WIND FLOW IS SOUTH OF
32N BETWEEN 30W AND 60W...EAST OF THE DEEP LAYER ATLANTIC-TO-
CARIBBEAN SEA TROUGH. BROAD SURFACE ANTICYCLONIC WIND FLOW IS
NORTH OF THE ITCZ TO 30N BETWEEN AFRICA AND THE ATLANTIC-TO-
CARIBBEAN SEA STATIONARY FRONT. MIDDLE TO UPPER LEVEL TROUGH
GOES FROM A CYCLONIC CIRCULATION CENTER NEAR 20N16W AT THE
MAURITANIA COAST JUST SOUTH OF MOROCCO TO 14N22W TO 8N29W TO
5N34W. MIDDLE TO UPPER LEVEL DRY AIR SURROUNDS THIS TROUGH.

$$
MT




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