[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 142349
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST FRI DEC 14 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N12W 6N20W 3N30W 1N40W 1S52W.
SCATTERED MODERATE CONVECTION IS WITHIN 180-200 NM EITHER SIDE
OF THE AXIS BETWEEN 30W-40W. SIMILAR CONVECTION IS WITHIN 60 NM
OF N OF AXIS BETWEEN 18W-23W.

DISCUSSION...
GULF OF MEXICO...
A FRONTAL BOUNDARY EXTENDS ACROSS THE FLORIDA PANHANDLE AND THE
NORTHERN GULF WATERS ENTERING THE STATE OF TEXAS AS A WARM FRONT
THEN CONTINUES OVER NE MEXICO AS A STATIONARY FRONT. THIS FRONT
EVENTUALLY CONNECTS TO A DEVELOPING LOW PRESSURE CENTER THAT IS
EXPECTED TO PUSH THROUGH THE U.S. GULF COAST STATES AND THE GULF
OF MEXICO DURING THE UPCOMING WEEKEND...BRINGING A NOTICEABLE
INCREASE IN WINDS AND ROUGH SEAS. A GALE WARNING HAS BEEN POSTED
FOR THE W GULF BEHIND THE FRONT FOR NLY WINDS IN THE 25-35 KT
RANGE. A MUCH COOLER AND DRIER AIRMASS WILL BE ADVECTED INTO THE
REGION WITH THIS FLOW. THIS EVENING...DOPPLER RADAR IS ONLY
DETECTING A FEW LIGHT SHOWERS OVER THE UPPER TEXAS COAST AND THE
FAR NW CORNER OF THE GULF. MUCH MORE ORGANIZED SHOWER AND TSTM
ACTIVITY IS OVER SOUTH-CENTRAL FLORIDA...INCLUDING THE AREA OF
LAKE OKEECHOBEE. THIS MOISTURE IS PRIMARILY TRIGGERED BY AN
ELONGATED SFC TROUGH THAT EXTENDS NE FROM THE REMNANTS OLGA IN
THE NW CARIBBEAN TO CENTRAL FLORIDA. CLOUDINESS WITH EMBEDDED
SHOWERS AND ISOLATED TSTMS IS ASSOCIATED WITH THESE FEATURES
COVERING  MOST THE EASTERN HALF OF THE GULF AND THE YUCATAN
PENINSULA. ALOFT...A RIDGE CONTINUES TO DOMINATE THE GULF
ANCHORED ON A HIGH OVER NORTHERN CENTRAL AMERICA.

CARIBBEAN SEA...
OLGA'S REMNANTS IS STILL SPINNING IN THE NW CARIBBEAN NEAR
19.6N85.6W. BUOY 42056 HAS BEEN VERY HELPFUL IN ESTIMATING THE
MINIMUM PRESSURE OF THIS LOW THAT IS CURRENTLY 1006 MB. THIS LOW
IS EXPECTED TO MOVE NW INTO THE YUCATAN PENINSULA BY SAT...THEN
WILL BE ABSORBED BY AN APPROACHING COLD FRONT ENTERING THE NW
CARIBBEAN EARLY SUN. THE LOW-LEVEL CIRCULATION IS VERY WELL
DEFINED ON SATELLITE PHOTOS WITH A SMALL CLUSTER OF MODERATE
CONVECTION JUST EAST OF THE CENTER. A DIFFLUENT PATTERN ALOFT IS
PROBABLY ENHANCING THIS CONVECTIVE ACTIVITY. FAIRLY DENSE CLOUD
BANDS WITH SCATTERED SHOWERS AND A FEW TSTMS ASSOCIATED WITH THE
OVERALL CIRCULATION OF THE REMNANTS OF OLGA ARE AFFECTING
WESTERN CUBA...THE YUCATAN PENINSULA...THE NW CARIBBEAN
INCLUDING ALSO THE GULF OF HONDURAS AND NORTHERN HONDURAS. THE
UPPER LEVEL PATTERN CONSISTS OF A RIDGE ACROSS THE WRN CARIBBEAN
ANCHORED ON A HIGH OVER CENTRAL AMERICA AND A TROUGH OVER THE
EAST AND CENTRAL PORTIONS OF THE BASIN ENTERING THE AREA FROM
THE ATLC. A FAIR AMOUNT OF CLOUDS WITH SCATTERED SHOWERS ARE
FOUND SOUTH OF THE TROUGH AXIS AFFECTING BETWEEN THE WINDWARD
ISLANDS AND THE ABC ISLANDS. TYPICAL PATCHES OF LOW LEVEL CLOUDS
WITH MAINLY LIGHT SHOWERS ARE SEEN OVER THE REMAINDER OF THE
BASIN. FRESH TO STRONG EASTERLY TRADE WINDS WILL PERSIST INTO
THE WEEKEND.

ATLANTIC OCEAN...
MOST OF AREA IS FAIRLY TRANQUIL UNDER THE INFLUENCE OF A RIDGE
ANCHORED ON A 1026 MB HIGH LOCATED NEAR 29N59W. RATHER TIGHT
GRADIENT TO THE S OF THE HIGH IS PRODUCING STRONG ELY TRADES S
OF 20N W OF 40W. A SFC TROUGH...PREVIOUSLY MENTIONED IS
GENERATING SCATTERED SHOWERS AND TSTMS OVER SOUTH-CENTRAL
FLORIDA AND THE FAR NW PORTION OF THE FORECAST REGION. ANOTHER
SFC TROUGH ENTERS THE AREA NEAR 31N31W THEN CONTINUES SW TO NEAR
24N42W. A WEAK SFC LOW HAS DEVELOPED WEST OF THE CANARY ISLANDS
ALONG THE SFC TROUGH THAT HAS BEEN OUT THERE DURING THE LAST FEW
DAYS. NO DEEP CONVECTION IS ASSOCIATED WITH THESES FEATURES.  A
LONGWAVE MID TO UPPER RIDGE/TROUGH PATTERN CONTINUES TO DOMINATE
THE DISCUSSION AREA. THE RIDGE EXTENDS FROM THE CARIBBEAN ENE TO
BEYOND 32N36W. THE UPPER-LEVEL TROUGH CONTROLS THE PATTERN
MAINLY E OF 5OW AND EXTENDS FROM THE EASTERN ATLANTIC TO THE
CENTRAL AND TROPICAL ATLANTIC ALONG 20N...INTO THE EASTERN
CARIBBEAN. THE INTERACTION OF THIS TROUGH WITH THE ITCZ IS
PRODUCING POCKETS OF MODERATE CONVECTION SOUTH OF 12N AND WEST
OF 50W...INCLUDING THE GUYANAS AND PARTS OF VENEZUELA. A
JETSTREAM BRANCH WITH CORE WINDS OF 90-110 KT ORIGINATES NEAR
THE SE BASE OF THE TROUGH AXIS AND EXTENDS NE CROSSING BETWEEN
THE CANARY/CAPE VERDE ISLANDS. WIDESPREAD CLOUDINESS WITH
EMBEDDED SCATTERED SHOWERS AND TSTMS ARE SOUTH OF THE JET AXIS.

$$
GR





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