[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071120
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST WED MAR 07 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1100 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N10W 5N20W 2N30W EQ40W EQ50W.
SCATTERED MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE
AXIS E OF 18W AND FROM 1S-3S BETWEEN 30W-38W. ISOLATED MODERATE
IS WITHIN 180 NM N OF THE AXIS BETWEEN 36W-44W.

...DISCUSSION...

GULF OF MEXICO...
A 1028 MB SFC HIGH PRES SYSTEM REMAINS ESTABLISHED ACROSS THE
AREA CENTERED OVER THE NE GULF NEAR 30N88W. LATEST QSCAT DATA
AND SFC OBS SHOW LIGHT ELY WINDS ACROSS THE E AND MIDDLE GULF
VEERING TO THE S IN THE W GULF ON THE WRN PERIPHERY OF THE
RIDGE. IN THE MID AND UPPER LEVELS...THE FLOW IS MAINLY FROM THE
WNW BETWEEN EXTENSIVE ZONAL FLOW OVER CENTRAL AMERICA AND WELL
DEFINED TROUGHING OVER THE ERN U.S. ASSOCIATED WITH A LARGE
POLAR VORTEX. BROKEN MID AND HIGH CLOUDINESS IS LOCATED N OF 27N
ESPECIALLY IN THE NE GULF CLOSER TO THE BASE OF THE DEEP TROUGH.
ABUNDANT DRY SINKING AIR EXISTS ELSEWHERE KEEPING SKIES FAIR TO
MOSTLY CLEAR. OVER THE NEXT COUPLE OF DAYS...THE HIGH PRES
SYSTEM MAY WEAKEN SLIGHTLY KEEPING WINDS LIGHT TO MODERATE. THE
MID AND UPPER PATTERN WILL LIKELY REMAIN NEARLY ZONAL BUT MAY
INCREASE IN MAGNITUDE AS SMALL IMPULSES/VORT MAXES MOVE ACROSS
THE SRN U.S.

CARIBBEAN...
REMNANT PATCHES OF LOW TO MID LEVEL CLOUDS...LEFT OVER FROM THE
DISSIPATED TROUGH/FRONT...ARE STILL LINGERING IN THE NW CARIB
STEERED BY MODERATE TO STRONG NELY FLOW. THIS FLOW IS POOLING
MOISTURE OVER HONDURAS...BELIZE...GUATEMALA AND S MEXICO AND
LIFTED OROGRAPHICALLY NEAR/OVER THE HIGH TERRAIN. SOME STATIONS
IN THESE COUNTRIES ARE REPORTING LIGHT SHOWERS. A SIMILAR SETUP
EXISTS OVER THE HIGH TERRAIN OF HISPANIOLA. ELSEWHERE MODERATE
ELY TRADES ARE BLOWING WITH ONLY A FEW PATCHES OF LOW-LEVEL
MOISTURE. ALOFT...THE FLOW IS RATHER ZONAL WITH A LARGE AMOUNT
OF DRY STABLE AIR ...ESPECIALLY E OF 78W...KEEPING MOST OF THE
MOISTURE PATCHES SHALLOW. NO BIG PATTERN CHANGES ARE EXPECTED IN
THE NEXT DAY OR TWO SO SIMILAR TRADES AND WEATHER CONDITIONS ARE
LIKELY.

WESTERN ATLANTIC...
DEEP LAYER TROUGHING COVERS THE MAJORITY OF THE ATLC W OF 50W
EXTENDING SWD FROM A LARGE POLAR LOW. TWO FRONTAL BOUNDARIES ARE
ASSOCIATED WITH THE TROUGH. ONE OF THESE HAS BEEN IN THE AREA
FOR QUITE SOMETIME AND IS ANALYZED ALONG 32N52W 26N63W THEN
STATIONARY ACROSS THE ERN BAHAMAS. BROKEN LOW AND MID LEVEL
CLOUDS AND EMBEDDED SHOWERS ARE WITHIN 180 NM ALONG AND AHEAD OF
THE COLD FRONT AND WITHIN 150 NM W OF THE STATIONARY PART OF THE
BOUNDARY. A PREFRONTAL TROF LIES 150 NM E OF THE FRONT ALONG
25N59W 21N67W NOTED BY GENTLE LOW-LEVEL CONVERGENCE SEEN IN
QSCAT DATA AND SAT IMAGES. THE OTHER FRONT IS RAPIDLY
PROGRESSIVE ENTERING THE AREA NEAR 32N58W EXTENDING WSW TO
29N77W THEN STATIONARY TOWARD THE SE GEORGIA COAST. THIS FRONT
IS CLEARLY MARKED BY A THIN ROPE LINE ON NIGHT CHANNEL VIS BUT
BECAUSE OF THE STABLE LOW-LEVELS BEHIND THE FIRST
FRONT...INDICATED BY COLD AIR STRATOCUMULUS CLOUDS...LIMITED
MOISTURE IS ASSOCIATED WITH THIS ONE. HOWEVER WV IMAGES DO SHOW
A PATCH OF MID-HIGH LEVEL CLOUDS N OF 27N W OF 60W ASSOCIATED
WITH A CLIPPER SYSTEM EMBEDDED IN THE DEEP LAYER TROUGH. NWP
MODELS SHOW THE LAYERED TROUGH HOLDING ON FOR THE NEXT DAY OR
TWO BEFORE PULLING NE TOWARD THE END OF THE WEEK. GFS IS HINTING
AT DEVELOPING A SFC TROUGH OR WEAK LOW IN THE BAHAMAS LATE
THU/FRI WHICH MAY PRODUCE SOME UNSETTLED WEATHER.

EASTERN ATLANTIC...
A 1035 MB HIGH PRES SYSTEM LOCATED A FEW HUNDRED NM S OF THE
AZORES NEAR 33N23W IS DOMINATING THE SFC PATTERN ACROSS THE ATLC
E OF 50W. THIS HIGH IS PRODUCING MODERATE TO STRONG TRADES
ACROSS A GOOD PORTION OF THE DISCUSSION ZONE. THE MAIN FEATURE
IN THIS AREA IS IN THE UPPER LEVELS WHERE A FAIRLY VIGOROUS 300
MB LOW IS LOCATED NEAR 26N42W. THIS LOW IS EMBEDDED AND CUTTING
OFF A LARGE UPPER RIDGE THAT COVERS MOST OF THE REGION. SWLY
UPPER LEVEL FLOW AND DIFFLUENCE TO THE E OF THE UPPER LOW IS
ADVECTING AND GENERATING A FAIR AMOUNT OF MOISTURE/SCATTERED
SHOWERS FROM 10N-32N BETWEEN 25W-40W. MODELS SHOW THE UPPER LOW
MOVING NWD AND OPENING INTO A TROUGH LATER TODAY OR TOMORROW.
THIS WILL LIKELY REDUCE THE FETCH OF MOISTURE ACROSS THE REGION
AS THE UPPER RIDGE GAINS CONTROL.

$$
CANGIALOSI


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