[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 102353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON MAR 10 2008

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 4N10W 1N20W 1S30W 2S40W INTO NE
BRAZIL NEAR 3S45W. CLUSTERS OF MODERATE TO STRONG CONVECTION ARE
WITHIN 150 NM N OF AXIS EAST OF 23W. SIMILAR CONVECTIVE ACTIVITY
IS FROM 3N TO THE AFRICAN COAST BETWEEN THE PRIME MERIDIAN AND
10W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 2100 UTC...A NEW COLD FRONT IS ENTERING THE NW CORNER OF
THE GULF FOLLOWED BY NE WINDS OF 20 TO 25KT. AT 2245Z...BUOY
42020 LOCATED NEAR 27N97W WAS REPORTING NE WINDS OF 30KT AND
SEAS TO 9 FT. A LINE OF SHOWERS AND TSTMS MARKS THE LEADING EDGE
OF THIS FRONTAL SYSTEM. ACCORDING TO LIGHTNING DATA...TSTMS ARE
MOST CONCENTRATED N OF 27N. THE MOSAIC DOPPLER RADAR FROM THE SE
U.S. ALSO SHOWS SCATTERED TO NUMEROUS SHOWERS WITH EMBEDDED
TSTMS OVER PARTS OF LOUISIANA AND EASTERN TEXAS. PATCHY SHALLOW
CLOUDINESS AND EMBEDDED LIGHT SHOWERS COVER THE REMAINDER OF THE
REGION...PARTICULARLY THE EASTERN GULF E OF 86W ENHANCED BY A
LOW-LEVEL TROUGH THAT LIES ALONG 86W N OF 24N. AN EARLIER ASCAT
PASS INDICATED SOME WIND SHIFT ASSOCIATED WITH THIS TROUGH.
ANOTHER SFC TROUGH IS ANALYZED NEAR THE COAST OF MEXICO AND THE
WESTERN PORTION OF THE BAY OF CAMPECHE. THIS TROUGH IS ALSO
PRODUCING BROKEN LOW LEVEL CLOUDS OVER THE SW QUADRANT OF THE
GULF. ALOFT...SWLY FLOW DOMINATES THE ENTIRE GULF AHEAD OF A
SHORT WAVE TROUGH MOVING ACROSS CENTRAL TEXAS AND NE MEXICO.
THESE WINDS ARE TRANSPORTING SOME UPPER LEVEL MOISTURE FROM THE
EPAC THROUGH CENTRAL MEXICO AND THE GULF INTO THE SE U.S..THE
COLD FRONT IS FORECAST TO REACH THE CENTRAL GULF TUE AFTERNOON
EXTENDING FROM THE FLORIDA PANHANDLE TO THE BAY OF CAMPECHE...
AND DISSIPATE TUE NIGHT INTO WED.

CARIBBEAN SEA...
A MID/UPPER LEVEL RIDGE ANCHORED ON A HIGH LOCATED JUST SOUTH OF
JAMAICA IN THE UPPER LEVELS DOMINATES MOST OF THE CARIBBEAN SEA
AND CENTRAL AMERICA...INCLUDING ALSO THE GREATER ANTILLES. A
BROAD AND ELONGATED MID-UPPER LEVEL TROUGH EXTENDS ACROSS THE
CENTRAL ATLC WITH THE TAIL END REACHING THE WINDWARD ISLANDS AND
NE VENEZUELA. THESE UPPER FEATURES ARE PRODUCING STRONG
SUBSIDENCE AND IMPLIED DRY AND STABLE AIS MASS MAINLY EAST OF
80W. AT THE SURFACE...THE REMNANTS OF A FRONTAL BOUNDARY
STRETCHES FROM CENTRAL CUBA TO THE YUCATAN PENINSULA. AT 21Z A
SFC TROUGH WAS ANALYZED ACROSS THIS AREA. ELSEWHERE...TYPICAL
FRAGMENTS OF OF LOW-LEVEL CLOUDS WITH MAINLY LIGHT SHOWERS ARE
MOVING ACROSS THE BASIN UNDER A NELY WIND FLOW. SOME OF THEM ARE
CURRENTLY APPROACHING THE VIRGIN ISLANDS AND PUERTO RICO. HIGH
PRES N OF AREA WILL PRODUCE MODERATE TRADE WINDS ACROSS THE AREA
DURING THE NEXT SEVERAL DAYS.

ATLANTIC OCEAN...
A COLD FRONT ENTERS THE REGION NEAR 31N60W THEN CONTINUES SW TO
NEAR 28N66W. AT THIS POINT...THE FRONT BECOMES STATIONARY AND
DISSIPATES ACROSS THE CENTRAL BAHAMAS/CUBA AND THE NW CARIBBEAN.
A 120-130 NM WIDE BAND OF LOW AND MID-LEVEL CLOUDS WITH
SCATTERED SHOWERS DEFINES THE FRONT ON SATELLITE IMAGERY. THE
PRESSURE GRADIENT BETWEEN THIS FEATURE AND A 1030 MB HIGH
EXITING THE MID ATLC STATES IS PRODUCING MODERATE NE WINDS OF
15-20 KT OVER THE W ATLC JUST BEHIND THE FRONT. AN EARLIER
QUIKSCAT PASS CONFIRMED THESE WIND SPEEDS. THIS CONDITION WILL
CONTINUE TO DIMINISH OVER THE NEXT COUPLE OF DAYS AS THE FRONT
DISSIPATES.

THE OTHER FEATURE OF INTEREST IS A SFC TROUGH THAT LIES ALONG
47W/48W FROM 24N-31N. THIS TROUGH IS A REFLECTION OF A
DISSIPATING CUT-OFF LOW WHICH HAS BEEN MOVING SLOWLY WWD DURING
THE PAST SEVERAL DAYS. WIDELY SCATTERED SHALLOW SHOWERS ARE
ASSOCIATED WITH THIS TROUGH MAINLY ON THE EAST SIDE. THIS SFC
TROUGH IS EMBEDDED IN THE N END OF A BROAD AND ELONGATED MID TO
UPPER LEVEL TROUGH EXTENDING ACROSS THE CENTRAL ATLC FROM AN
UPPER LOW SITUATED NEAR 32N43W TO THE FAR SE CARIBBEAN AND NE
VENEZUELA. STRONG SWLY UPPER FLOW ON THE E SIDE OF THE TROUGH IS
ADVECTING ABUNDANT UPPER LEVEL MOISTURE FROM N SOUTH AMERICA ALL
THE WAY NE ACROSS THE TROPICAL ATLC BEYOND 23N37W. A BROAD RIDGE
ANCHORED ON A HIGH LOCATED JUST SOUTH OF THE CAPE VERDE ISLANDS
DOMINATES THE REMAINDER OF THE ATLANTIC FORECAST AREA. A 1027 MB
HIGH CENTERED S OF THE AZORES NEAR 34N27W EXTENDS A RIDGE ACROSS
THE E ATLC. THE COMBINATION OF THIS HIGH AND LOWER PRES OVER
AFRICA IS PRODUCING A SWATH OF NE WINDS OF 20-25 KT BETWEEN THE
CANARY/CAPE VERDE ISLANDS AND THE WEST COAST OF AFRICA. THE HIGH
IS FORECAST BY THE COMPUTER MODELS TO SHIFT NE AND WEAKEN.

$$
GR



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