[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081801
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT MAR 08 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 1N20W 1S40W 2S52W. CLUSTERS OF
MODERATE TO STRONG CONVECTION ARE N OF 3N TO THE AFRICAN COAST
BETWEEN THE PRIME MERIDIAN AND 11W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM FROM EQ-3N BETWEEN 18W-24W...AND FROM
3N-7N BETWEEN 37W-43W.

...DISCUSSION...

THE GULF OF MEXICO...

THE STRONG COLD FRONT THAT YESTERDAY MOVED ACROSS THE GULF
CROSSED SOUTH FLORIDA EARLY THIS MORNING WITH A WELL DEFINED
LINE OF SHOWERS AND TSTMS. THIS FRONTAL SYSTEM IS CURRENTLY OVER
THE WEST ATLANTIC...JUST EAST OF FLORIDA AND THE NW CARIBBEAN.
BEHIND THE FRONT...HIGH PRES IS GRIPPING THE GULF AND NE MEXICO
USHERING A COLD AND MORE STABLE AIR MASS. A 1028 MB HIGH IS NEAR
TAMPICO MEXICO WHILE ANOTHER HIGH PRES CENTER IS OVER EASTERN
TEXAS. COLD AIR HAS PENETRATED INTO THE SIERRA MADRE MOUNTAINS
AS DEPICTED BY A RATHER UNIFORM STRATUS CLOUDS COVER AND
STATIONARY FRONT IS ANALYZED ACROSS SOUTH-CENTRAL MEXICO. THIS
TYPE OF CLOUDINESS ALSO COVERS THE BAY OF CAMPECHE. CONVECTIVE
CLOUDS STREETS ARE FORMING PARALLEL TO THE WINDS OVER THE
EASTERN GULF DUE TO THE ADVECTION OF COLD AIR OVER RELATIVELY
WARM WATERS. GALE FORCE WINDS WERE BLOWING BEHIND THE FRONT OVER
PARTS OF THE EASTERN AND CENTRAL GULF THIS MORNING BUT THEY ARE
DIMINISHING NOW. A WIND ADVISORY REMAINS IN EFFECT FOR SOUTH
FLORIDA UNTIL 4 PM EST THIS AFTERNOON. AS OF 1500 UTC...A SFC
TROUGH IS ANALYZED OVER THE NW QUADRANT OF THE GULF PROBABLY
ASSOCIATED WITH A SECONDARY FRONT. HIGH PRES WILL REMAIN IN
CONTROL OF THE WEATHER PATTERN ACROSS THE GULF DURING THE NEXT
FEW DAYS PRODUCING MODERATE TO FRESH EASTERLY WINDS MAINLY SOUTH
OF 25N THROUGH MON.

THE CARIBBEAN SEA...

A STRONG COLD FRONT FROM THE ATLC EXTENDS ACROSS WESTERN
CUBA...THE CAYMAN ISLANDS AND THE NW CARIBBEAN INTO HONDURAS.
A DEEP LAYERED TROUGH EXTENDING FROM THE GREAT LAKES TO SE
LOUISIANA AND THE NORTHERN GULF OF MEXICO WATERS SUPPORTS THE
FRONTAL ZONE. THE LEADING EDGE OF THIS FRONT IS MARKED BY A LINE
OF SHOWERS AND TSTMS. LIGHTING DATA INDICATES THAT TSTMS ARE
MORE CONCENTRATED OVER AND JUST N OF THE NW BAHAMAS. HAVANA
REPORTED LIGHT RAIN AND NLY SUSTAINED WINDS OF 15-20 KT WITH THE
PASSAGE OF THE FRONT THIS MORNING. THE FRONT WILL MOVE ACROSS
CENTRAL CUBA THIS AFTERNOON THROUGH SUNDAY MONDAY THEN STALL AND
WEAKEN. COMPUTER MODELS SUGGEST THAT AN AREA OF MOISTURE
ASSOCIATED WITH THIS FRONT WILL PERSIST OVER THE GULF OF
HONDURAS AND BELIZE ON SUNDAY. ALOFT...A MID TO UPPER RIDGE
ANCHORED ON A HIGH LOCATED SOUTH OF JAMAICA DOMINATES MOST OF
THE BASIN BUT PARTICULARLY THE CENTRAL CARIBBEAN. AN UPPER LEVEL
TROUGH INDUCED BY A LARGE CUT OFF LOW SITUATED IN THE EASTERN
ATLANTIC REACHES THE FAR E CARIBBEAN. WIDESPREAD SUBSIDENCE IS
ASSOCIATED WITH THESE UPPER SYSTEMS E OF 80W. FRAGMENTS OF LOW
LEVEL CLOUDS WITH EMBEDDED MAINLY LIGHT SHOWERS DOT THE AREA
EAST OF THE AFOREMENTIONED COLD FRONT.

THE ATLANTIC OCEAN....

THE MAIN WEATHER FEATURE IS THE STRONG COLD FRONT THAT MOVED
THROUGH SOUTH FLORIDA THIS MORNING. AS OF 1500 UTC...THE FRONT
ENTERS THE DISCUSSION AREA NEAR 31N78W THEN CONTINUES SWWD
ACROSS THE NW BAHAMAS AND WESTERN CUBA INTO THE CARIBBEAN SEA.
GALE FORCE WINDS AHEAD OF THE FRONT WILL DIMINISH THIS
AFTERNOON. A LINE OF SHOWERS AND TSTMS MARKS THE LEADING EDGE OF
THIS FRONTAL SYSTEM. THE OTHER FEATURE OF INTEREST IS A 1011 MB
LOW SPINNING NEAR 28N37W. THIS LOW REMAINS QUASI-STATIONARY AND
HAS WEAKENED SINCE YESTERDAY. A SWIRL OF LOW CLOUDS DEFINES THE
CYCLONE CENTER WITH SCATTERED SHOWERS AND PROBABLY ISOLATED
TSTMS TO THE NE OF THE LOW. A SFC TROUGH EXTENDS FROM THE LOW
SWWD TO 18N43W. TIGHT PRES GRADIENT BETWEEN THIS CYCLONIC
CIRCULATION AND A 1031 MB HIGH PRES OVER THE CENTRAL ATLC IS
PRODUCING A LARGE AREA OF MODERATE TO STRONG NE WINDS IN THE NW
QUADRANT OF THE LOW. ACCORDING TO THE GFS COMPUTER MODEL...THE
LOW WILL SLOWLY DRIFT SW AND CONTINUE TO WEAKEN DURING THE REST
OF THE WEEKEND LEAVING AN OPEN SFC TROUGH.
ALOFT...A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE AREA. A JET
STREAM BRANCH WITH CORE WINDS OF 90-110 KT LIES BETWEEN THE
PREVIOUSLY MENTIONED LARGE CUT-OFF LOW OVER THE EASTERN ATLC AND
A BROAD UPPER-LEVEL HIGH LOCATED SE OF THE CAPE VERDE ISLANDS
NEAR 12N21W. UPPER S AND SW FLOW ON THE WESTERN SIDE OF THE HIGH
IS ADVECTING PATCHY HIGH LEVEL CLOUDS FROM N SOUTH AMERICA
ACROSS THE TROPICAL ATLC. THESE WINDS ARE ALSO ENHANCING
SCATTERED MODERATE CONVECTION EITHER SIDE OF THE ITCZ AXIS AND
WEST OF 30W.

$$
GR


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