[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301740
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI JAN 30 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...THE ITCZ...
THE ITCZ AXIS IS PRETTY ACTIVE TODAY. IT IS CENTERED ALONG 5N10W
1N20W CROSSING THE EQUATOR AT 25W THEN EXTENDING ALONG 1S35W
INTO NE BRAZIL NEAR 4S45W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 130-140 NM N OF AXIS BETWEEN 21W-40W.
SIMILAR CONVECTION IS SOUTH OF THE AXIS NEAR 1.5N12W. CLUSTERS
OF SCATTERED MODERATE TO STRONG CONVECTION ARE FROM THE EQUATOR
TO THE COAST OF AFRICA BETWEEN THE PRIME MERIDIAN AND 8W.

...DISCUSSION...

GULF OF MEXICO...
AT 1500 UTC...A LONG-WAVE TROUGH EXTENDING FROM THE GREAT LAKES
AREA TO CENTRAL TEXAS SUPPORTS A COLD FRONT THAT STRETCHES FROM
CENTRAL FLORIDA TO 23N90W ENTERING MEXICO THROUGH THE ISTHMUS OF
TEHUANTEPEC. NOAA BUOY 42055 LOCATED NEAR 22N94W IS ALREADY
REPORTING GALE FORCE WINDS OF 35 KT. A GALE WARNING IS IN EFFECT
FOR THE SW PORTION OF THE GULF. IN THE WAKE OF THE FRONT...A
COOLER AIRMASS IS IN PLACE ADVECTED BY N-NE 20 TO 35 KT WINDS
ACROSS THE NRN AND WRN GULF. COLD AIR HAS PENETRATED INTO THE
SIERRA MADRE MOUNTAINS AS DEPICTED BY A RATHER UNIFORM STRATUS
CLOUDS COVER AND A STATIONARY FRONT IS ANALYZED THERE. A LINE OF
SHOWERS WITH WITH EMBEDDED TSTMS IS AT THE LEADING EDGE OF THE
FRONT MAINLY OVER THE SE GULF. SOME OF THIS ACTIVITY IS BEING
ENHANCED BY UPPER DIVERGENCE ASSOCIATED WITH A JET STREAM
MAXIMUM OVER THE SE CONUS. THE FRONT WILL GET A SECOND PUSH
SOUTH THIS AFTERNOON AS A SHORTWAVE OVER THE GULF MOVES SE. THE
FRONT WILL EXIT THE AREA LATE TODAY. AHEAD OF THE FRONT...DRY
AIR AND ATMOSPHERIC STABILITY IS INHIBITING ANY DEEP CONVECTION.
HIGH PRES WILL BUILD OVER THE NORTHERN GULF DURING THE UPCOMING
WEEKEND. ACCORDING TO THE GFS COMPUTER MODEL...A STRONGER COLD
FRONT WILL MOVE ACROSS THE GULF REGION MON...ACCOMPANIED BY
STRONG NLY WINDS.

CARIBBEAN SEA...
A SFC TROUGH IS ANALYZED OVER THE EASTERN CARIBBEAN ALONG 63W S
OF 20N. A DIFFLUENT PATTERN ALOFT ASSOCIATED WITH A BROAD
UPPER-LEVEL RIDGE CENTERED OVER N SOUTH AMERICA IS ENHANCING
CONVECTION OVER THE WINDWARD ISLANDS. ANOTHER PATCH OF MOISTURE
IS NEAR THE N END OF THE TROUGH LIKELY RELATED TO AN UPPER LOW
SPINNING JUST NORTH OF PUERTO RICO. MODERATE TO FRESH TRADE
WINDS ARE BLOWING ACROSS THE REGION. A QUIKSCAT PASS FROM THIS
MORNING SHOWED ELY WINDS OF UP TO 30 KT JUST OFFSHORE THE
COLOMBIAN COAST. THESE WINDS ARE EXPECTED TO DECREASE DURING THE
REST OF THE DAY AS A COLD FRONT ENTERS WESTERN CUBA AND THE NW
CARIBBEAN TONIGHT. N-NE 20-25 KT WINDS AND RELATIVELY COOLER AND
DRIER AIR ARE EXPECTED TO BUILD BEHIND THE FRONT. ELSEWHERE...
GENERALLY FAIR CONDITIONS PERSIST WITH DEEP LAYER DRY AIR IN
PLACE. HOWEVER...TYPICAL ISOLATED SHOWERS ARE BEING CARRIED BY
THE TRADE WINDS ACROSS THE BASIN.

ATLANTIC OCEAN...
A COLD FRONT ENTERS THE FORECAST AREA NEAR 31N74W THEN CONTINUES
SW ACROSS CENTRAL FLORIDA AND THE GULF OF MEXICO. THIS FRONT IS
EXPECTED TO REACH THE MONA PASSAGE BY LATE SATURDAY. MOSAIC
DOPPLER RADAR FROM THE SE CONUS REVEALS SCATTERED SHOWERS AND
ISOLATED TSTMS OVER CENTRAL FLORIDA ASSOCIATED WITH THE FRONT. A
LINE OF TSTMS IS DEVELOPING ALONG THE LEADING EDGE OF THE FRONT.
THIS CONVECTIVE LINE IS APPROACHING THE FLORIDA KEYS AND SW
FLORIDA. THE REMAINDER OF THE REGION IS UNDER THE INFLUENCE OF A
1031 MB HIGH LOCATED NEAR 32N33W WHICH IS PRODUCING MOSTLY FAIR
WEATHER. A SWATH OF 20-25 KT ELY WINDS IS NOTED ACROSS THE
TROPICS AROUND THE SOUTHERN PERIPHERY OF THIS HIGH THAT IS
FORECAST BY THE COMPUTER MODELS TO REMAIN NEARLY STATIONARY
DURING THE NEXT 24 HOURS OR SO. ANOTHER COLD FRONT CLIPS THE
DISCUSSION AREA CROSSING JUST EAST OF THE CANARY ISLANDS.
ALOFT...SW FLOW AHEAD OF THE AFOREMENTIONED LONG-WAVE TROUGH IS
NOTED OVER THE FAR NW AREA. A RIDGE DOMINATES MUCH OF THE WEST
AND CENTRAL ATLC ANCHORED ON AN UPPER-LEVEL HIGH NEAR 26N47W. AN
UPPER-LEVEL TROUGH EXTENDS FROM THE CANARY ISLANDS SW TO NEAR
20N30W THEN WWD TO NEAR 17N42W. SUBSIDENCE AND THE ASSOCIATED
DRY AIR IS NOTED ALONG THE TROUGH AXIS. WLY WINDS DOMINATES THE
DEEP TROPICS.

$$
GR









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