[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 010541
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU FEB 01 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
0515 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N10W SURGING S CROSSING THE EQUATOR
NEAR 22W THEN BECOMING MORE ZONAL ALONG 2S30W 3S40W AND INTO
NE BRAZIL. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM N OF
THE AXIS BETWEEN 13W-23W.

...DISCUSSION...
GULF OF MEXICO...
THE GULF LIES ON THE N SIDE OF A VERY BROAD MID TO UPPER LEVEL
RIDGE CENTERED IN THE TROPICAL E PAC. ABUNDANT DRY AIR ALOFT
EXISTS ACROSS THE REGION AS INDICATED ON WV IMAGES...EXCEPT FOR
SOME PATCHY HIGH CLOUDS BEING ADVECTED ACROSS S MEXICO AND THE
BAY OF CAMPECHE. AT THE SFC...A 1008 MB LOW IS LOCATED OFF THE
SE TEXAS COAST NEAR 28N96W WITH A WARM FRONT EXTENDING EWD ALONG
29N92W 28N86W. SFC OBS AND AN EARLIER QSCAT PASS MAKE THE FRONT
EASY TO FIND WITH WINDS VEERING FROM S-SE S OF THE FRONT TO
STRONGER ENE WINDS N DUE TO THE TIGHTENED PRES GRAD BETWEEN THE
LOW/FRONT AND A PAIR OF 1023 MB HIGHS IN THE CAROLINAS. MOSAIC
DOPPLER RADAR FROM THE SE SHOWS MOST OF THE STRATIFORM
OVERRUNNING PRECIP WELL INLAND...SOME OF IT IN THE FROZEN FORM.
THERE ARE LIKELY ISOLATED SHOWERS ACROSS THE N GULF...ESPECIALLY
N OF THE WARM FRONT. A STATIONARY FRONT REMAINS ALONG THE SLOPES
OF THE SIERRA MADRE IN MEXICO AS LOW CLOUDS ARE STILL BANKED UP
AGAINST THE TERRAIN. LOOKING AHEAD OVER THE NEXT DAY OR
TWO...THE WEAK LOW/WARM FRONT WILL TRANSFORM INTO A COLD FRONT
AS AN UPPER TROUGH CURRENTLY OVER THE WRN U.S. DIGS SE. NWP
MODELS SUGGEST THAT THIS FRONT WILL NOT BE A VERY QUICK MOVER
SLOWLY MOVING THRU REGION OVER THE NEXT COUPLE DAYS.

CARIBBEAN SEA...
PLENTY OF DRY AIR ALOFT EXISTS EVERYWHERE IN THE CARIBBEAN
PROVIDING SINKING STABLE AIR. THE DRIEST AIR LIES ABOVE THE SE
CARIB AND THE WINDWARD ISLANDS WHERE UPPER LEVEL CONFLUENCE IS
ENHANCING STABILITY. IN THE LOW LEVELS OF THE ATMOS...ELY TRADES
ARE GENERATING AND DRIVING SOME PATCHES OF MOISTURE SCATTERED
ACROSS THE AREA. THESE PATCHES ARE VERY THIN IN THE CENTRAL AND
ERN CARIB BUT APPEAR A LITTLE THICKER AND MORE ORGANIZED IN THE
NW CARIB WHERE THE FLOW DEVELOPS A SLY COMPONENT IN RESPONSE TO
THE LOW/FRONT IN THE N GULF. SPEAKING OF THE TRADES...THE FLOW
IS FAIRLY MODERATE THIS MORNING MAINLY IN THE 15-20 KT
RANGE...EXCEPT FOR THE TYPICAL STRONGER WINDS N OF COLOMBIA.
WINDS IN THE CENTRAL AND E CARIB ARE FORECAST TO INCREASE OVER
THE NEXT FEW DAYS AS HIGH PRES RIDGING BECOMES ESTABLISHED AND
STRENGTHENS IN THE CENTRAL ATLC.

ATLANTIC OCEAN...
AN UPPER TROUGH IS MAINLY N OF THE AREA EXTENDING FROM
NEWFOUNDLAND TO 25N58W. THIS SHORT WAVE IS PART OF A VERY LARGE
POLAR UPPER LOW/TROUGH IN CANADA. MOIST STRONG SWLY UPPER LEVEL
FLOW E OF THE SHORT WAVE AXIS IS PROVIDING ENERGY TO GENERATE A
SWATH OF MOISTURE N OF 26N BETWEEN 45W-55W. S AND W OF THE AREA
OUTLINED...DRY AIR ALOFT COVERS MOST OF THE SW AND S CENTRAL
ATLC INTO THE CARIB. AT THE SFC...THERE ARE A PAIR OF OLD
FRONTAL BOUNDARIES ASSOCIATED WITH THE UPPER TROUGH. ONE IS
ANALYZED FROM 32N61N TO THE CENTRAL BAHAMAS AND THE OTHER IS
FURTHER E ALONG 30N56W 24N63W TOWARD THE N COAST OF HAITI. WHILE
DEEP MOISTURE IS LIMITED NEAR THE SFC BOUNDARIES...ESPECIALLY
THE WRN ONE...THEY ARE SIGNIFICANT WITH QSCAT DATA SHOWING A
WELL-DEFINED CHANGE IN WIND DIR AND SPEED. THE UPPER LEVEL
PATTERN IN THE CENTRAL AND E ATLC IS HIGHLY AMPLIFIED WITH A
LARGE RIDGE COVERING THE REGION BETWEEN 30W-50W AND A SHARP DEEP
TROUGH EXTENDING FROM MADEIRA TO THE CAPE VERDE ISLANDS.
A FAIR AMOUNT OF MOISTURE...ASSOCIATED WITH THE UPPER TROUGH AND
SWLY FLOW MENTIONED EARLIER...IS LOCKED INTO THE RIDGE N OF 27N.
THIS MOISTURE DRIES OUT ON THE DOWNWARD BRANCH BETWEEN THE RIDGE
AND TROUGH...NAMELY E OF 37W.

$$
CANGIALOSI




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