[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 262346
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED 26 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 5N10W 1N35W 2N60W 3N80W. SMALL AREA
OF SCATTERED STRONG CONVECTION FROM THE EQ NWD TO 2N BETWEEN
27W-31W.

...DISCUSSION...

GULF OF MEXICO...
AFTER A FAIRLY TRANQUIL/BENIGN PATTERN DURING THE LAST 48
HOURS...CHANGES APPEAR IN STORE OVER THE GULF THROUGH THE END OF
THE WEEK.  CURRENTLY...A TEMPORARY WARMING TREND IS UNDERWAY
ACROSS THE AREA AS THE NEARLY STATIONARY SURFACE HIGH PREVIOUSLY
OVER THE CENTRAL GULF IS BEGINNING TO SLIDE EWD ALLOWING MOIST
SLY FLOW.  THIS TREND WILL BE SHORT-LIVED THOUGH AS A WEAK TO
MODERATE COLD FRONT...CURRENT PUSHING SWD OVER THE SE UNITED
STATES...EMERGES INTO THE N GULF LATER TONIGHT THEN BECOMES
STATIONARY OVER THE CENTRAL AND W GULF ALONG 27N/28N THU.
MEANWHILE...THE E PORTION OF THE BOUNDARY WILL CONTINUE SWD
CLEARING S FLORIDA EARLY FRI...ALBEIT IN A WEAKENING STATE. THE
ENTIRE FRONT WILL INITIALLY BE DRY AND WITHOUT SIGNIFICANT UPPER
SUPPORT UNTIL A PROGRESSIVE MIDDLE TO UPPER LEVEL TROUGH OVER
THE SW UNITED STATES ADVANCES TO THE CENTRAL UNITED STATES THU
AND FRI AT WHICH TIME IMPROVING UPPER DYNAMICS/LIFT...W OF
90W...WILL PRODUCE INCREASING CLOUDINESS AND SHOWERS OVER THE NW
GULF.  THE UPPER TROUGH THEN IGNITES A FRONTAL WAVE/LOW OFF THE
SE COAST OF TEXAS FRI ALONG WITH WIDESPREAD CLOUDINESS AND
SHOWERS/THUNDERSTORMS. THE FRONTAL LOW IS EXPECTED TO MIGRATE
EWD ALONG THE N GULF COAST THROUGH THE WEEKEND WHICH WOULD
PRODUCE AN UNSETTLED/WET PATTERN N OF 25N OVER THE WEEKEND.

CARIBBEAN...
A RATHER FLAT/ZONAL MIDDLE TO UPPER LEVEL PATTERN CONTINUES OVER
THE CARIBBEAN WITH AN E/W ORIENTED RIDGE ALIGNED ALONG S
AMERICA.  MODERATE/STRONG SUBSIDENCE ALSO BLANKETS THE AREA
MAINTAINING DRY/STABLE CONDITIONS ALOFT. AT THE SURFACE...
THE S EXTENT OF A CENTRAL ATLC COLD FRONT ENTERS THE AREA OVER
THE N LEEWARD ISLANDS EXTENDING WSW AS A REMNANT FRONTAL TROUGH
TO 15N76W.   LOW LEVEL MOISTURE POOLING ALONG THE BOUNDARY IS
PRODUCING A 90 NM WIDE BAND OF BROKEN/OVERCAST CLOUDINESS AND
SCATTERED SHOWERS OVER THE NE CARIBBEAN N OF 15N TO JUST S OF
HISPANIOLA AND PUERTO RICO.  THIS AREA OF MOISTURE AND
ASSOCIATED SHOWER ACTIVITY WILL SLOWLY MIGRATE NWD REACHING
PUERTO RICO AND HISPANIOLA DURING THE NEXT DAY OR TWO. OVER THE
REMAINDER OF THE AREA...LOW LEVEL DRY AIR WHICH OVERSPREAD THE W
CARIBBEAN BEHIND COLD FRONT EARLIER IN THE WEEK WILL REMAIN
ENTRENCHED KEEPING CLOUDINESS AND SHOWERS AT A RELATIVE MINIMUM.

ATLANTIC OCEAN...
A BROAD MID/UPPER TROUGH COVERS THE W TWO-THIRDS OF THE ATLC W
OF 35W COMPRISED OF MULTIPLE SHORTWAVE DISTURBANCE. THE MOST
NOTABLE OF THESE SHORTWAVE FEATURES IS LOCATED OVER THE CENTRAL
TO E ATLC ALONG 35W WITH ATTENDANT COLD FRONT EXTENDING FROM
32N32W SW ALONG 21N50W WHERE IT BECOMES QUASI-STATIONARY TO THE
N LEEWARD ISLANDS. THE BEST UPPER LIFT/DYNAMICS ALONG THE FRONT
SKIRTS THE N EXTENT OF THE AREA W OF THE AZORES WITH ASSOCIATED
SCATTERED MODERATE CONVECTION N OF 29N BETWEEN 25W-35W.
ELSEWHERE ALONG THE FRONT...BROKEN TO OVERCAST CLOUDINESS AND
WIDELY SCATTERED SHOWERS ARE WITHIN 360 NM E OF FRONT N OF 25N
AND WITHIN 120 NM EITHER SIDE OF BOUNDARY S OF 25N.  THE SECOND
SHORTWAVE OF NOTE LIES OVER THE W ATLC ROUGHLY HALFWAY BETWEEN
THE SE UNITED STATES AND BERMUDA TRAILING SW TO FLORIDA.  THIS
FEATURE IS ESSENTIALLY MOISTURE STARVED AND ONLY ABLE TO SQUEEZE
OUT PATCHY CLOUDINESS AND A FEW ISOLATED SHOWERS.   ELSEWHERE
OVER THE W ATLC...A 1020 MB HIGH IS LOCATED NEAR 25N60W WITH
RIDGE STRETCHING WESTWARD OVER THE CENTRAL BAHAMAS AND THROUGH
THE FLORIDA STRAITS.  POST-FRONTAL NORTHERLY FLOW AND COLD AIR
ADVECTION...ALBEIT WEAKER THAN EARLIER IN THE WEEK...IS
MAINTAINING THE TYPICAL WINTER TIME OPEN CELLULAR STRATOCUMULUS
CLOUDINESS.  OVER THE E ATLC...A 1022 MB STATIONARY SURFACE HIGH
IS LOCATED NEAR 27N27W WITH ASSOCIATED RIDGE EXTENDING SW TO
20N40W.  THERE IS LITTLE IN THE WAY OF SIGNIFICANT CLOUDINESS OR
WEATHER AS EARLIER VISIBLE SATELLITE IMAGERY INDICATES THE AREA
OF AFRICAN DUST/DRY AIR HAS SPREAD WESTWARD NOW E OF 35W.

$
RHOME


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