[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAR 20 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N11W 3N26W 1N34W CROSSING THE
EQUATOR NEAR 40W TO 2S44W. SCATTERED MODERATE TO STRONG
CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE AXIS BETWEEN
15W-18W. ISOLATED MODERATE TO STRONG CONVECTION IS FROM THE
EQUATOR TO 4N BETWEEN 18W-24W AND FROM 3N-6N BETWEEN 43W-48W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH OVER THE ERN CONUS IS SUPPORTING A COLD FRONT
THAT HAS JUST PASSED THROUGH S FLORIDA. HOWEVER...THE BOUNDARY
BECOMES GREATLY KINKED TO THE WSW INDUCED BY A 1014 MB FRONTAL
WAVE NEAR 23N87W. THIS LOW PRES AREA HAS BECOME BETTER DEFINED
THROUGHOUT THE DAY AND HAS LIKELY ENHANCED THE GAP WIND EVENT IN
THE GULF OF TEHUANTEPEC. THE FRONT IS STATIONARY FROM THE LOW
SWD THROUGH THE YUCATAN PENINSULA AND BANKED UP AGAINST THE
HIGHER TERRAIN OF WRN HONDURAS AND GUATEMALA. DENSE LOW-LEVEL
CLOUDS AND EMBEDDED SHALLOW SHOWERS ARE WITHIN 180 NM W OF LOW
AND FRONT. DEEPER SCATTERED CONVECTIVE PRECIP IS JUST AHEAD OF
THE BOUNDARY OVER THE WRN PORTION OF THE YUCATAN CHANNEL. THE
REMAINDER OF THE GULF IS FAIRLY QUIET WITH VISIBLE IMAGERY
SHOWING CLEAR SKIES N OF 27N AND SCATTERED FAIR WEATHER
STRATOCUMULUS CLOUDS S OF 27N. N TO NE WINDS REMAIN STRONG W OF
THE FRONT TO 94W OR SO...THEN SLACKEN W OF THERE DUE TO THE
RELAXED PRES GRADIENT S OF A 1027 MB HIGH OVER SE TEXAS.

CARIBBEAN SEA...
AN UPPER TROUGH LINGERS OVER THE E CARIB WHILE A UPPER HIGH SITS
OVER THE TURKS AND CAICOS. THIS PATTERN IS KEEPING THE
ATMOSPHERE ALOFT STABLE...ESPECIALLY S OF 17N E OF 70W WHERE THE
UPPER FLOW IS MOST CONFLUENT. THE ONLY EXCEPTION IS OVER THE FAR
NW CARIB WHERE A STALLED FRONTAL BOUNDARY AND STRONG SWLY FLOW
ALOFT IS ENHANCING SCATTERED TSTMS OVER THE NE PORTION OF THE
YUCATAN PENINSULA. VISIBLE IMAGERY SHOWS A SMALL-SCALE LOW
SPINNING JUST E OF THE FRONT IN THE BAY OF HONDURAS NEAR
17N86W...ANALYZED 1014 MB. THIS LOW IS ALSO ENHANCING SCATTERED
SHOWERS AND ISOLATED TSTMS WITHIN 90 NM OF THE CENTER.
ELSEWHERE...PATCHES OF LOW-LEVEL CLOUDS AND EMBEDDED SCATTERED
SHOWERS ARE STREAMING ACROSS THE SEA DRIVEN BY MODERATE TO
STRONG TRADES. THE THICKEST PATCHES ARE E OF 70W...ESPECIALLY
OVER THE LESSER ANTILLES. THE AIRMASS IS STILL COOLER AND DRIER
THAN NORMAL OVER PUERTO RICO AND THE VIRGIN ISLANDS WITH TEMPS
MOSTLY IN THE 70'S F AND DEWPOINTS IN THE LOW 60'S F.

ATLANTIC...
A COLD FRONT CONTINUES TO MOVE FAIRLY QUICKLY EWD IN THE W ATLC
FROM 32N71W TO 26N78W TO EXTREME S FLORIDA. LOW-LEVEL
CONVERGENCE ALONG THE BOUNDARY AND A SWLY UPPER JET IS PRODUCING
SCATTERED SHOWERS AND TSTMS WITHIN 90 NM E OF THE FRONT N OF
26N. LIGHTNING DATA SHOWS A DECLINE IN THE NUMBER OF STRIKES
OVER THE PAST FEW HOURS. A DEEP LAYER HIGH PRES RIDGE IS
CENTERED TO THE E OF THE FRONT ALLOWING TRANQUIL WEATHER
CONDITIONS TO PREVAIL ACROSS MUCH OF THE WESTERN ATLC. DEEP
LAYER TROUGHING LIES OVER THE CENTRAL ATLC ON THE S SIDE OF A
LARGE MID TO UPPER LOW NEAR 35N42W. AN ASSOCIATED COLD FRONT
ENTERS THE AREA NEAR 32N38W CONTINUING SW ALONG 23N42W 15N52W.
SCATTERED SHOWERS AND TSTMS ARE WITHIN 300 NM E OF THE FRONT N
OF 27N. VERY LARGE N SWELLS CONTINUE TO AFFECT THE REGION
BETWEEN THIS LOW/FRONT AND A 1023 MB HIGH NEAR 26N64W. THESE
SWELLS WERE INITIALLY PRODUCED BY A LARGE POWERFUL LOW IN THE N
ATLC AND HAVE BEEN PROLONGED DUE TO A SERIES OF ASSOCIATED WEAK
LOWS IN THE SAME REGION.

BESIDES FOR A BROKEN AREA OF MID-HIGH LEVEL CLOUDS AND POSSIBLE
SHOWERS WITHIN 150 NM SE OF A LINE FROM 15N49W TO 22N31W...THE E
ATLC REMAINS QUIET LYING TO THE S OF MODEST SFC RIDGING AND IN A
STABLE ENVIRONMENT ALOFT ON THE N SIDE OF AN UPPER HIGH NEAR
10N21W.

$$
CANGIALOSI


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