[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 032342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI APR 03 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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...
THE ITCZ AXIS IS CENTERED ALONG 6N10W 3N15W CROSSING THE EQUATOR
NEAR 23W TO 4S40W. SCATTERED MODERATE CONVECTION IS WITHIN 180
NM OF THE AXIS BETWEEN 12W-21W AND WITHIN 60 NM OF THE AXIS
BETWEEN 27W-35W.

...DISCUSSION...

THE GULF OF MEXICO...
A COLD FRONT IS SLOWING IN ITS FORWARD PROGRESSION FROM FORT
MYERS FLORIDA TO THE N PORTION OF THE YUCATAN PENINSULA. THIS
DECELERATION IS DUE THE ASSOCIATED RETREATING UPPER TROUGH OVER
THE GREAT LAKES. SATELLITE IMAGERY AND DOPPLER RADAR REVEAL
MULTILAYER CLOUDINESS AND SCATTERED SHOWERS WITHIN 90 NM OF THE
FRONT. LIGHTNING DATA SUGGESTS LITTLE EMBEDDED TSTM ACTIVITY.
NWP MODELS ARE IN AGREEMENT IN SHOWING THE FRONT STALL LATER
TONIGHT AND THEN LIFT N AS A WEAKENING WARM FRONT SAT WITH
DIMINISHING MOISTURE. A SPRAWLING MID-UPPER HIGH IS BUILDING
BEHIND THE FRONT CENTERED JUST S OF MEXICO OVER THE GULF OF
TEHUANTEPEC. THIS FEATURE IS EXPECTED TO DRIFT E THROUGH THE
WEEKEND...DOMINATING THE WEATHER PATTERN OVER THE CENTRAL AND E
PART. A STRONG COLD FRONT

THE CARIBBEAN SEA...
WATER VAPOR IMAGERY AND SOUNDING DATA REVEAL ABUNDANT MID-UPPER
LEVEL DRY AIR ACROSS THE REGION. THE ATMOSPHERE IS MOST STABLE
IN AN UPPER CONFLUENT ZONE OVER THE SW CARIBBEAN BETWEEN A LARGE
UPPER RIDGE OVER THE GULF OF TEHUANTEPEC AND TROUGHING OVER THE
CENTRAL CARIBBEAN. IN THE LOWER LEVELS...THE ONLY NOTABLE AREA
OF MOISTURE IS OVER THE LEEWARD ISLANDS ASSOCIATED WITH AN
INVERTED TROUGH LOCATED JUST E OF THE ISLANDS ALONG 60W. SEVERAL
OF THE SFC STATIONS HAVE BEEN REPORTING SHOWERS OVER THE PAST
FEW HOURS AND THIS WILL LIKELY CONTINUE THROUGH TONIGHT AS THE
WEAK BOUNDARY SLOWLY CROSSES THE ISLAND CHAIN. TRADES ARE
GENERALLY E TO SE 15-20 KT...EXCEPT SLY 20-25 KT OVER THE NW
CARIBBEAN IN RESPONSE TO A FRONT OVER THE SE GULF OF MEXICO.
THIS FRONT IS NOT FORECAST TO ENTER THE CARIBBEAN.

THE ATLANTIC OCEAN...
A COUPLE OF FRONTS EXTENDING INTO THE SUBTROPICS ARE THE MAIN
TALKING POINTS IN THE DISCUSSION ZONE. THE STRONGER FRONT IS
OVER THE FAR NW PORTION FROM 31N77W TO CENTRAL FLORIDA.
LOW-LEVEL CONVERGENCE ALONG THE BOUNDARY COUPLED WITH AN UPPER
JET IS TRIGGERING SCATTERED SHOWERS AND TSTMS N OF 28N E OF THE
FRONT TO 70W. SW WINDS ARE ON THE STRONG SIDE...20-25 KT...
AHEAD OF THE FRONT BUILDING SEAS TO 10 FT AT BUOY 440O4 LOCATED
NEAR 31N73W. THIS FRONT HAS SUFFICIENT SUPPORT TO CONTINUE SE
FOR ANOTHER DAY OR TWO BEFORE STALLING. THE OTHER FRONT IS
DISSIPATING AND STATIONARY OVER THE CENTRAL ATLC EXTENDING S
FROM A 1014 MB LOW NEAR 31N42W TO 24N46W TO 21N52W. SCATTERED
SHOWERS AND ISOLATED TSTMS LIE N OF 27N BETWEEN 32W-45W...MAINLY
TIED TO A LARGER SCALE UPPER LOW. WEATHER CONDITIONS ARE FAIRLY
TRANQUIL ELSEWHERE BENEATH MID-UPPER RIDGES. THE EXCEPTION IS
S OF 7N BETWEEN 40W AND 60W WHERE AN UPPER DIFFLUENT PATTERN IS
ENHANCING SCATTERED SHOWERS AND TSTMS...MAINLY INLAND OVER SOUTH
AMERICA.

$$
CANGIALOSI





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