[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 240515
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT FEB 24 2007

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0415 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N12W 4N19W 2N20W CROSSING THE
EQUATOR NEAR 36W TO INLAND OVER SOUTH AMERICA NEAR 2S48W.
SCATTERED/NUMEROUS STRONG CONVECTION IS FROM THE EQUATOR TO 3N
BETWEEN 7W-15W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 150 NM ALONG THE COAST OF SOUTH AMERICA
FROM 47W-54W. SCATTERED THUNDERSTORMS ARE FROM THE EQUATOR TO 3N
BETWEEN 35W-42W.

...DISCUSSION...

GULF OF MEXICO...
STRONG UPPER LEVEL RIDGE REMAINS OVER THE GULF ALONG 87W
CONTINUING FAIR CONDITIONS OVER MUCH OF THE GULF TONIGHT.
MID/UPPER LEVEL CLOUDS CONTINUE TO SPREAD OVER THE NW GULF BEING
ADVECTED ACROSS MEXICO AND TEXAS IN ADVANCE OF THE DEVELOPING
STORM SYSTEM OVER THE CENTRAL PLAINS. A WARM FRONT IS ALONG THE
LEADING EDGE OF THIS AIR MASS AND EXTENDS BETWEEN CORPUS CHRISTI
AND GALVESTON TEXAS SE TO 25N90W. OTHERWISE...HIGH PRESSURE IS
CENTERED ALONG THE SOUTH CAROLINA COAST WITH THE TAIL END OF AN
ATLC COLD FRONT SWEEPING ACROSS S JUST OFF THE FLORIDA E COAST
USHERING IN SLIGHTLY DRIER AIR. ANOTHER COLD FRONT WILL MOVE
INTO TEXAS LATER TONIGHT INTO THE DAY SAT THEN WILL MOVE OFF THE
COAST INTO THE NW GULF LAT IN THE DAY INTO SUN MORNING CLEARING
THE GULF EARLY NEXT WEEK. SCATTERED SHOWERS/THUNDERSTORMS WILL
DEVELOP OVER THE FAR N GULF AHEAD OF THE FRONT MAINLY SAT NIGHT
THEN SHIFT TO EAST ACROSS THE GULF FOR THE REMAINDER OF THE
WEEKEND.

CARIBBEAN...
MID/UPPER LEVEL HIGH IS CENTERED ALONG THE COAST OF NICARAGUA
WITH THE AXIS EXTENDING EASTWARD TO THE SOUTHERN MOST WINDWARD
ISLANDS. AS A RESULT...THIS IS PRODUCING STRONG SUBSIDENCE AND
DRY UPPER AIR OVER THE REGION KEEPING ANY SHOWER ACTIVITY FAIRLY
SUPPRESSED. A BAND OF POSSIBLE SHOWERS...LIKELY A REMNANT OF AN
OLD FRONTAL BOUNDARY...DOES EXTEND FROM OVER HISPANIOLA/
WINDWARD PASSAGE TO JAMAICA THEN TO THE NE COAST OF NICARAGUA.

ATLANTIC...
A LARGE AND COMPLEX POLAR VORTEX IS MOVING E OF THE CANADIAN
MARITIMES WITH BROAD CYCLONIC FLOW SWEEPING ACROSS THE W/CENTRAL
ATLC. AN 974 MB LOW WITH HURRICANE FORCE WINDS IS CENTERED WELL
N OF THE AREA AND IS SHOWING SIGNS OF WEAKENING ALTHOUGH ITS
ASSOCIATED COLD FRONT REMAINS STRONG WITH WINDS IN THE REGION
BELOW GALE FORCE. THE COLD FRONT ENTERS THE REGION NEAR 32N56W
EXTENDING SW ALONG 26N65W THEN W TO THE NORTHERN BAHAMAS AND THE
S FLORIDA COAST NEAR 25N80W. THE PRE-FRONTAL TROUGH IS ABOUT 250
NM SE OF THE FRONT...EXTENDING FROM 30N52W TO 22N63W. WHILE THE
FRONT ITSELF IS RATHER DRY...THERE ARE SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS WITHIN UP TO 120 NM E OF THE TROUGH N OF
23N AND WITHIN 120 NM W OF THE TROUGH N OF 27N. THE FRONT IS
EXPECTED TO STALL AS IT REACHES THE N CARIBBEAN BY SUN MORNING
WITH THE MID-LATITUDE PORTION CONTINUING TO THE E AND PRODUCING
A BAND OF SHOWERS/THUNDERSTORMS. ELSEWHERE...THE SURFACE LOW
LOCATED JUST OFF THE N COAST OF HISPANIOLA HAS LOST ITS
IDENTITY...AND IS NOW A SURFACE TROUGH EXTENDING FROM 23N68W TO
20N71W WITH ISOLATED SHOWERS WITHIN 75 NM EITHER SIDE OF THE
TROUGH. THIS FEATURES IS EXPECTED TO DISSIPATE OVER THE NEXT 12
TO 24 HRS. A STRONG 1029 MB HIGH IS CENTERED W OF THE CANARY
ISLANDS NEAR 29N25W WITH THE SURFACE RIDGE EXTENDING SW TO
23N50W. THIS STRONG HIGH CONTINUES TO SUPPRESS THE ITCZ AXIS
WELL TO THE SOUTH. THE UPPER LEVEL MID-LATITUDE FLOW IS
CHARACTERIZED BY A LOW AMPLITUDE RIDGE ALONG 30W. BENEATH THAT
FLOW...A CUT-OFF MID/UPPER LEVEL TROUGH EXTENDS FROM 21N25W SW
TO 14N34W WITH ITS OWN PATCH OF MODERATE/STRONG SUBSIDENCE
WITHIN A 200/250 NM RADIUS.

$$
WALLACE




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