[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191718
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED 19 JAN 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1645 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N10W 3N45W 8N70W 4N80W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 3N-8N BETWEEN 25W-47W.

...DISCUSSION...

GULF OF MEXICO...
A SPLIT FLOW REGIME CONTINUES OVER THE GLFMEX AND MEXICO WITH
THE N BRANCH OF THE JET STREAM CONFINED WELL N OF THE AREA WHILE
THE INACTIVE S STREAM EXTENDS FROM SE TEXAS EWD OVER CENTRAL
FLORIDA. WATER VAPOR IMAGERY INDICATES COPIOUS MIDDLE TO UPPER
LEVEL PACIFIC MOISTURE ADVECTION INTO W MEXICO BUT THIS PLUME
DRIES OUT AS IT RIDES UP AND OVER A RIDGE OVER INTERIOR MEXICO.
AS A RESULT...ONLY STREAKS OF HIGH CLOUDINESS EXTEND ACROSS THE
N GULF OF MEXICO.   AT THE LOWER LEVELS...POST-FRONTAL NLY FLOW
AND ASSOCIATED COLD AIR STRATOCUMULUS CLOUDS PREVAIL OVER ALL
BUT THE EXTREME W GULF OF MEXICO WHERE RETURN FLOW IS SPARKING
CLOUDINESS AND WIDELY SCATTERED SHOWERS ALONG A COASTAL TROUGH
FROM SE TEXAS TO VERACRUZ MEXICO.  THIS ACTIVITY SHOULD PERSIST
TODAY AND TONIGHT PRIOR TO DRYING OUT ON THU.  FURTHER N...A
SHORTWAVE TROUGH AND ATTENDANT COLD FRONT DROPPING QUICKLY SWD
OVER THE E UNITED STATES WILL CLIP THE NE GLFMEX AND FLORIDA
LATER TONIGHT AND TOMORROW.  HOWEVER...THIS SYSTEM WILL LACK
APPRECIABLE MOISTURE WITH ONLY A FEW WIDELY SCATTERED SHOWERS
PRIMARILY OVER N FLORIDA AND ALONG THE E FLORIDA COAST.

CARIBBEAN...
WATER VAPOR IMAGERY INDICATES THAT MIDDLE TO UPPER LEVEL
DRY/STABLE AIR DOMINATES THE ENTIRE AREA.  THE MAIN FEATURES OF
NOTE ARE A NEARLY STATIONARY MIDDLE TO UPPER LEVEL RIDGE
EXTENDING FROM N PORTIONS OF S AMERICA NW OVER CENTRAL AMERICA
AND A BROAD TROUGH EXTENDING SWD FROM THE W ATLC TO A BASE NEAR
CUBA. ATTENDANT COLD FRONT PULLS UP STATIONARY NEAR THE MONA
PASSAGE THEN SW TO PANAMA.  WIDELY SCATTERED SHOWERS ARE NOTED
WITHIN 240 NM NW OF FRONT BECOMING MORE NUMEROUS OVER THE SW
CARIBBEAN S OF 14N W OF 80W. ELSEWHERE W OF FRONT...POST-FRONTAL
NLY FLOW AND COLD AIR STRATOCUMULUS CLOUDS PREVAIL WITH ENHANCED
CLOUDINESS NOTED ALONG WINDWARD FACING SLOPES OF CENTRAL
AMERICA. SE OF THE FRONT...A WEAK LOW LEVEL TROUGH ALONG 60W IS
IGNITING SCATTERED SHOWERS AND A FEW ISOLATED THUNDERSTORMS OVER
THE WINDWARD ISLANDS WITH WIDELY SCATTERED SHOWERS OVER THE
LEEWARD ISLANDS.

ATLANTIC...
BROAD MIDDLE TO UPPER LEVEL TROUGH DOMINATES THE E UNITED STATES
AND W ATLC W OF 55W. A SHORTWAVE TROUGH JUST E OF BERMUDA IS
ROTATING THROUGH THIS PATTERN AND PRODUCING SCATTERED MODERATE
CONVECTION ALONG A SURFACE COLD FRONT FROM 32N52W TO THE MONA
PASSAGE.  THIS ACTIVITY IS PRIMARILY FOCUSED N OF 25N IN LINE
WITH THE STRONGEST DYNAMICS/LIFT WHICH IS QUICKLY TRANSITIONING
N OF THE AREA.  W OF THE FRONT...STRONG POST-FRONTAL
NORTHERLIES...COLD AIR ADVECTION...AND A FIELD OF BROKEN
STRATOCUMULUS CLOUDS PREVAIL.  OVER THE CENTRAL TO E ATLC...A
LARGE DEEP LAYERED LOW NEAR 27N35W WITH A NEARLY VERTICALLY
STACKED 1008 MB SURFACE LOW.  THIS SYSTEM DOMINATES THE WEATHER
WITH A LARGE AREA OF SCATTERED MODERATE CONVECTION FROM 23N-32N
BETWEEN 25W-35W.  THE SYSTEM SHOULD SLOWLY WEAKEN AS IT MOVES NW
AT 10-15 KT.  OVER THE TROPICAL ATLC...UPPER LEVEL DIFFLUENT
FLOW ON THE SOUTH SIDE OF THE AFOREMENTIONED DEEP LAYERED LOW IS
PRODUCING ENHANCED ITCZ CONVECTION BETWEEN 25W-45W.

$$
RHOME




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