[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170539
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT FEB 17 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 5N9W 4N20W 2N31W...CROSSING THE
EQUATOR NEAR 38W...1S40W INTO NORTHEASTERN BRAZIL NEAR 2S44W.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 150 NM
EITHER SIDE OF THE AXIS E OF 17W AND W OF 32W. ISOLATED MODERATE
IS WITHIN 120 NM EITHER SIDE BETWEEN 24W-29W.

...DISCUSSION...
THE GULF OF MEXICO...
FAIR WEATHER IS THE RULE ACROSS THE GULF THIS EARLY MORNING AS
MOST OF THE LOW TO MID LEVEL CLOUD DECK HAS THINNED AND PUSHED
SWD WITH THE FRONT NOW IN THE NW CARIB. THE ONLY AREA OF THICK
CLOUD COVER IS IN THE SW GULF NEAR A LINGERING WEAK STATIONARY
FRONT ALONG THE SIERRA MADRE MOUNTAINS....BUT EVEN THESE CLOUDS
ARE BEING ERODED AND PUSHED SWD. SCATTERED COLD AIR
STRATOCUMULUS CLOUDS ARE SEEN ON IR IMAGES OVER MOST OF THE ERN
HALF OF THE REGION. THE SFC FLOW IN THE W GULF HAS RELAXED A
GREAT DEAL SINCE YESTERDAY AT THIS TIME AS THE HIGH PRES SYSTEM
HAS WEAKENED AND BECOME CENTERED IN THE N CENTRAL GULF. NLY
WINDS ARE MODERATE IN THE E GULF DUE TO THE TIGHTENED PRES
GRADIENT BETWEEN HIGH PRES IN THE CENTRAL GULF AND LOW PRES IN
THE ATLC. THESE NLY WINDS ARE ADVECTING IN A COLD AIRMASS WITH
TEMPS ALREADY IN THE 20'S F IN N FLA. THE COLD AIR WILL BE
REINFORCED BY A QUICK MOVING DRY COLD FRONT WHICH WILL BE
PUSHING THRU THE ENTIRE REGION TODAY INTO EARLY SUN. THIS WILL
RAMP UP THE NLY WINDS AGAIN IN ITS WAKE AS ANOTHER STRONG HIGH
PRES SYSTEM BUILDS S.

THE CARIBBEAN SEA...
THE TAIL END OF A WEAKENING COLD FRONT EXTENDS FROM CENTRAL CUBA
TO HONDURAS ALONG 22N78W 20N83W 15N87W. THE FRONT IS MARKED
MOSTLY BY A SURGE IN NLY WINDS WELL INDICATED BY A QSCAT PASS
NEAR 00 Z. A WEAK PRE-FRONTAL TROUGH IS ANALYZED FROM 20N79W TO
14N82W SHIFTING THE WINDS FROM E/NE TO NW PRIOR TO THE FRONTAL
PASSAGE. LOTS OF LOW TO MID LEVEL CLOUDS LIE OVER CUBA AND PARTS
OF THE NW CARIB...ALTHOUGH THERE ISN'T MUCH SHOWER ACTIVITY
EMBEDDED IN THIS AS SUGGESTED BY DOPPLER RADAR IN CUBA.
ELSEWHERE THE MAIN WEATHER FEATURE IS A VERY BROAD STRONG UPPER
LEVEL RIDGE STRETCHING ACROSS THE REGION. THIS RIDGE IS
SUPPLYING AN ABUNDANT AMOUNT OF DRY AIR/SUBSIDENT FLOW ALOFT
SUPPRESSING ANY SIGNIFICANT TSTM ACTIVITY. THE DRIEST AIR IS IN
THE UPPER CONFLUENT ZONE BETWEEN HISPANIOLA AND
VENEZUELA/COLOMBIA. BENEATH THE STRONG MID LEVEL CAP...SMALL
PATCHES OF LOW-LEVEL MOISTURE ARE BEING STEERED BY LIGHT TO
MODERATE ELY TRADES E OF 78W. THE NLY WINDS ARE ANTICIPATED TO
SLACKEN LATER TODAY IN THE NW CARIB BUT INCREASE AGAIN ON SUN
BEHIND THE NEXT COLD FRONT.

THE ATLANTIC OCEAN...
A COLD FRONT ENTERS THE AREA NEAR 32N57W AND CONTINUES SW ALONG
26N68W TO THE COAST OF CUBA NEAR 22N77W. LOW LEVEL LIFT NEAR THE
FRONT ALONG WITH A SUBTROPICAL JET RACING THRU THE AREA IS
PRODUCING BROKEN TO OVERCAST MULTILAYERED CLOUDS WITH EMBEDDED
SHOWERS WITHIN 400 NM NW OF THE FRONT. A SFC TROUGH ENTERS THE
AREA NEAR BERMUDA AT 32N65W AND CONTINUES WSW TO 29N80W...ADDING
A LITTLE CYCLONIC CURVATURE TO THE PREDOMINANT STRONG NW WINDS
BLOWING OFFSHORE THE SE U.S. SWLY GALE FORCE WINDS ARE OCCURRING
WITHIN 240 NM AHEAD OF THE FRONT N OF 29N. THE REMAINDER OF THE
SFC PATTERN IN THE ATLC AREA IS DOMINATED BY THE SRN PERIPHERY
OF A 1028 MB HIGH NEAR 35N28W. THIS IS SUPPLYING MOSTLY FAIR
WEATHER AND MODERATE TRADES ACROSS A GOOD PORTION OF THE CENTRAL
AND E ATLC. THE MID TO UPPER LEVEL PATTERN HAS AMPLIFIED A
LITTLE...AS EXPECTED...DOMINATED BY A LARGE RIDGE OVER THE WRN
AND CENTRAL ATLC W OF 40W AND A BROAD TROUGH E OF THERE. WHILE
THE PATTERN IS MORE AMPLIFIED THERE IS LITTLE SIGNIFICANT
MOISTURE BEING GENERATED OUTSIDE OF THE ITCZ.

$$
CANGIALOSI




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