[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231946
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED 23 MAR 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
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N1W 2N15W 2N30W THEN INLAND OVER S
AMERICA NEAR THE EQUATOR AND 50W.  WIDELY SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM EITHER SIDE
OF ENTIRE ITCZ AXIS INCLUDING SW PORTIONS OF AFRICA AND COASTAL
AREAS OF BRAZIL.

...DISCUSSION...

GULF OF MEXICO...
ANOTHER ACTIVE DAY FOR THE GLFMEX AS A POTENT S STREAM
DISTURBANCE MOVING ACROSS THE TENNESSEE VALLEY CONTINUES TO
TRIGGER STRONG THUNDERSTORMS OVER THE NE GULF AND N FLORIDA.
THIS ACTIVITY IS FOCUSED NEAR THE ENTRANCE REGION OF A 100+ KT
UPPER JET OVER THE SE UNITED STATES.  AT THE SURFACE... A 1003
MB SURFACE LOW RESIDES N OF THE AREA WITH TRAILING COLD FRONT
ENTERING THE GULF OVER THE FLORIDA PANHANDLE NEAR APALACHICOLA
SWD INTO THE BAY OF CAMPECHE. THE COLD FRONT MARKS THE LEADING
EDGE OF A MODERATE CONTINENTAL AIRMASS WITH POST-FRONTAL
TEMPERATURES RETURNING TO MORE SEASONABLE VALUES.  ASSOCIATED
CONVECTION PRECEDES THE FRONT BY 100-200 NM LYING ALONG A
DIFFUSE PRE-FRONTAL TROUGH FROM N CENTRAL FLORIDA TO THE CENTRAL
GULF NEAR 24N89W. WATER VAPOR IMAGERY SHOWS THAT THE MIDDLE TO
UPPER LEVEL TROUGH AND ASSOCIATED JET IS NOW LIFTING QUICKLY
NEWD AND THE FRONT WILL BE LOSING ITS UPPER SUPPORT DURING THE
NEXT 12 HOURS.  EXPECT CURRENT STRONG CONVECTIVE ACTIVITY TO
GRADUALLY WEAKEN WITH WIDELY SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS REMAINING ALONG THE COLD FRONT AS IT CLEARS S
FLORIDA TONIGHT AFTER MIDNIGHT BRING A BRIEF RESPITE FROM THE
NEAR SUMMER LIKE CONDITIONS YESTERDAY AND TODAY.  THE FRONT THEN
BECOMES STATIONARY OVER THE FLORIDA STRAITS THU MORNING AND
BEGINS TO RETREAT NWD THU AND FRI. WARM/MOIST CONDITIONS WILL
RETURN ACROSS THE S HALF OF THE GULF AND S FLORIDA AS THE FRONT
LIFTS NWD.

CARIBBEAN...
PERSISTENT MIDDLE TO UPPER LEVEL RIDGE REMAINS ACROSS THE AREA
EXTENDING E/W ALONG 11N/12N.  THE RIDGE IS ANCHORED BY A
WELL-DEFINED ANTICYCLONE OVER THE SE CARIBBEAN NEAR 12N65W.  THE
RIDGE WILL EFFECTIVELY BLOCK THE UPSTREAM COLD FRONT CURRENTLY
ADVANCING ACROSS THE GULF EXPECTED TO BECOME STATIONARY JUST N
OF THE AREA TONIGHT.  LOW LEVEL MOISTURE POOLING AHEAD OF THE
FRONT MAY SPARK A FEW ISOLATED TO WIDELY SCATTERED SHOWERS OVER
THE YUCATAN CHANNEL...YUCATAN PENINSULA...BELIZE...AND N
GUATEMALA TONIGHT AND EARLY THU.  OTHERWISE...VERY DRY
CONDITIONS THROUGHOUT THE ENTIRE ATMOSPHERE SHOULD CONTINUE TO
RESTRICT SHOWER ACTIVITY THROUGH THE END OF THE WEEK ACROSS MOST
OF THE AREA SAVE SOME ISOLATED CELLS MOVING ACROSS THE LESSER
ANTILLES WITH THE ELY TRADES.

ATLANTIC...
CONVECTION AHEAD OF A POTENT S STREAM SHORTWAVE MOVING NEWD OVER
UNITED STATES HAS DEVELOPED OVER THE EXTREME W ATLC N OF 28N W
OF 73W.  THIS ACTIVITY SHOULD LIFT QUICKLY NWD TODAY WITH THE
UPPER LEVEL DISTURBANCE WITH WIDELY SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ACCOMPANYING THE ATTENDANT COLD FRONT WHICH WILL
MOVE ACROSS FLORIDA TODAY EXTENDING FROM BERMUDA TO THE N
BAHAMAS BY THU MORNING.  COLD FRONT THEN WEAKENS AS IT MOVES
INTO THE CENTRAL ATLC FRI WITH ONLY A NARROW BAND OF SHOWERS
ALONG ITS LEADING EDGE.  ELSEWHERE...THE PATTERN IS BECOMING
INCREASING AMPLIFIED AS A SECOND SHORTWAVE DIPS SEWD OVER THE
CENTRAL ATLC CLIPPING THE N PORTION OF THE AREA BETWEEN 40W-50W.
ATTENDANT COLD FRONT ENTERS THE AREA ALONG 32N37W TRAILING SW TO
TO 27N53W.  THE FRONT IS MOISTURE STARVED WITH LIMITED
CLOUDINESS OR PRECIPITATION.  A NARROW BAND OF SCATTERED SHOWERS
ACCOMPANIES A PRE-FRONTAL TROUGH ALONG 32N32W 26N40W 23N53W.
STRONGER DYNAMICS/LIFT MAY CLIP TH EXTREME N PORTION OF THE
AREA...N OF 27N...TONIGHT INTO THU AS THE SHORTWAVE REACHES ITS
SOUTHERNMOST POSITION.  THIS SHOULD BE ENOUGH TO GENERATE A LINE
OF SCATTERED SHOWERS/THUNDERSTORMS ALONG THE N EXTENT OF THE
COLD FRONT WHICH WILL EXTEND FROM 32N21W THROUGH 24N50W TO
22N43W BY THU MORNING.  FRONT THEN BECOMES LESS ACTIVE LATE THU
AND THU NIGHT AS IT APPROACHES THE CANARY ISLANDS.   OVER THE E
ATLC...MODERATE/STRONG SUBSIDENCE IN THE UPPER LEVELS AND VERY
DRY AIR IN THE LOWER LEVELS MOVING OFF W AFRICA ARE LARGELY
SUPPRESSING CLOUDS AND PRECIPITATION OVER THE AREA. DRY AIR
PENETRATES WELL INTO THE TROPICAL WATERS RESTRICTING ITCZ
CONVECTION S OF 4N.

$$
RHOME





This weather bulletin was brought to you by:
www.nashvilleweather.net