[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 052340
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT 05 FEB 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 2N25W 1N38W 4N53W.  ISOLATED
MODERATE CONVECTION IS S OF 3N W OF 28W.

...DISCUSSION...

GULF OF MEXICO...
HIGHLY AMPLIFIED RIDGING PATTERN ALOFT EXISTS OVER THE GULF
COURTESY A POTENT SHORTWAVE TROUGH WHICH HAS CARVED OUT AN
UNUSUALLY DEEP TROUGH OVER THE EPAC AND BAJA PENINSULA. PATTERN
LOOKS A LITTLE EL-NINOISH WITH AN 130 KT SUBTROPICAL JET SENDING
TONS OF PAC MOISTURE UP AND OVER THE RIDGE RESULTING IN
WIDESPREAD CLOUDINESS OVER A GOOD PORTION OF CENTRAL MEXICO THRU
THE US BETWEEN LOUISIANA AND NEW MEXICO WITH HEAVY RAINS OVER
THE SW USA/MEXICO.  AT THE LOW LEVELS...POST-FRONTAL NE FLOW
WITH COLD AIR ADVECTION CONTINUE TO PRODUCE A LARGE FIELD OF
OPEN-CELLULAR STRATOCUMULUS CLOUDS OVER ALL BUT THE NE GULF.
FLORIDA REMAINS PRIMARY CLOUD FREE EXCEPT FOR SOME ATLC
CLOUDINESS AND ISOLATED SHOWERS ALONG THE E COASTAL COUNTIES.
POTENT SHORTWAVE TROUGH CURRENTLY OVER THE BAJA PENINSULA WILL
MOVE NEWD THROUGH THE SW AND CENTRAL USA OVER THE NEXT 48 HOURS
WITH ATTENDANT COLD FRONT APPROACHING THE NW GULF LATE SUN NIGHT
INTO MON.  EXPECT INCREASING CLOUDINESS AND SHOWERS/TSTMS AHEAD
OF FRONT BEGINNING LATE SUN. LOW LEVEL FLOW WILL VEER THROUGH
THE WEEKEND WITH MODERATE RETURN FLOW DEVELOPING OVER THE W GULF
BY SUN AND NE TO ELY FLOW OVER THE E GULF AND FLORIDA.

CARIBBEAN SEA...
MIDDLE TO UPPER LEVEL RIDGE DOMINATES THE SW HALF OF THE
CARIBBEAN WITH AXIS ALONG CENTRAL AMERICA THE WHILE W ATLC
TROUGH DOMINATES THE NE HALF OF THE CARIBBEAN. RESULTING FLOW IS
PRIMARILY NW TO W WITH MODERATE TO STRONG SUBSIDENCE PRODUCING
VERY DRY/STABLE CONDITIONS ALOFT. SIGNIFICANT WEATHER IS
CONFINED TO SHALLOW BASED SHOWERS PRIMARILY FOCUSED WITHIN 60 NM
EITHER SIDE OF A DISSIPATING COLD FRONT ENTERING THE AREA OVER
THE WINDWARD PASSAGE TO NEAR ROATAN STATIONARY INTO N HONDURAS.
SECOND AREA OF SHOWERS EXIST ALONG A WEAK LOW LEVEL TROUGH
EXTENDING FROM THE VIRGIN ISLANDS WSW TO JUST S OF HISPANIOLA
NEAR 16N72W THEN SW TO E PANAMA.  ELSEWHERE...MAINLY DRY
CONDITIONS PREVAIL ESPECIALLY OVER THE E CARIBBEAN.  INCREASING
LOW LEVEL MOISTURE AND SHOWER ACTIVITY IS EXPECTED OVER THE E
CARIBBEAN DURING THE NEXT 24 HOURS AS THE UPSTREAM FRONTAL
BOUNDARY APPROACHES... SOMEWHAT HERALDED BY THICKENING CLOUDS
OVER THE WINDWARD ISLANDS TONIGHT.

ATLANTIC OCEAN...
HIGH AMPLITUDE TROUGH-RIDGE-TROUGH PATTERN PREVAILS OVER THE
ATLC WATERS WITH TROUGH W OF 50W TO THE E COAST OF THE UNITED
STATES...RIDGE BETWEEN 30W-50W...AND TROUGH E OF 30W INTO NW
AFRICA.  PERSISTENT W ATLC TROUGH HAS AMPLIFIED ONCE AGAIN AS A
DISTINCT UPPER LOW JUST SW OF BERMUDA STRENGTHENS A 1004 MB LOW
NEAR 29N66W.  THE UPPER SYSTEM'S INCREASING DYNAMICS HAS
RESULTED IN UPPER LEVEL DIVERGENCE AND ASSOCIATED SHOWER/TSTMS
ACTIVITY ALONG THE ATTENDANT COLD FRONT STRETCHING FROM 28N62W
23N63W TO THE NW TIP OF HAITI. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 23N-31N BETWEEN 57W-66W ALSO ASSOCIATED WITH
THE COLD CORE OF THE LOW. ELSEWHERE W OF FRONT...POST-FRONTAL
NLY FLOW...COLD AIR ADVECTION...AND TYPICAL COLD AIR
STRATOCUMULUS CLOUDS PREVAIL TO THE FLORIDA E COAST. FURTHER
E...LARGE SCALE DIFFLUENCE NEAR A SURFACE TROUGH IS SUPPORTING
WIDESPREAD CLOUDINESS AND WIDELY SCATTERED MODERATE CONVECTION
OVER THE CENTRAL ATLC N OF 21N BETWEEN 40W-46W. EXPECT UPPER W
ATLC TROUGH TO SHARPEN THROUGH LATE SUNDAY WHEN AFOREMENTIONED
LOW SW OF BERMUDA BEGINS TO LIFT NEWD.  OVER THE E
ATLC...CONFLUENT FLOW AND MIDDLE TO UPPER LEVEL SUBSIDENCE IS
PRODUCING DRY/STABLE CONDITIONS ALOFT WITH AFRICAN DUST
PREVAILING IN THE LOW LEVELS E OF THE CAPE VERDE ISLANDS.

$$
BLAKE


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