[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151738
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN APR 15 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 4N10W 1N25W 2N35W CROSSING THE
EQUATOR AT 46W INTO NE BRAZIL NEAR 2N50W. A CLUSTER OF MODERATE
TO ISOLATED STRONG CONVECTION IS FROM EQ-4N BETWEEN 11N-15W.
SCATTERED MODERATE CONVECTION IS ALONG THE ITCZ AXIS BETWEEN
26W-36W. CLUSTERS OF MODERATE TO STRONG CONVECTION HAVE BEGUN TO
DEVELOP OVER SW AFRICA.

...DISCUSSION...

GULF OF MEXICO...
THE MAIN WEATHER FEATURE ACROSS THE FORECAST REGION TODAY IS A
STRONG COLD FRONT CURRENTLY MOVING SE ACROSS THE STATE OF
FLORIDA AND THE SE PORTION OF THE GULF. AS OF 15Z...THE COLD
FRONT EXTENDS SW FROM A 992 MB SFC LOW OVER THE CAROLINAS
THROUGH TAMPA BAY...THE SE QUADRANT OF THE GULF AND THE YUCATAN
PENINSULA TO NEAR 16N93W. A WIDE BAND OF STRONG SHOWERS/TSTMS
ACCOMPANIED BY DAMAGING WINDS AND HAIL IS ASSOCIATED WITH THE
FRONT. THIS FEATURE CROSSED TAMPA BAY THIS MORNING. THE
PRELIMINARY LOCAL STORM REPORT FROM THIS AREA HAS INDICATED
GUSTY WINDS OF 40 TO 50 MPH...HAIL AND A TORNADO WITH THE
PASSAGE OF THIS FRONTAL BOUNDARY. THE COLD FRONT IS EXPECTED TO
MOVE ACROSS SOUTH FLORIDA THIS AFTERNOON WITH THE RISK OF SEVERE
WEATHER CONDITIONS. AS A RESULT...ALL MAINLAND SOUTH FLORIDA IS
UNDER A TORNADO WATCH UNTIL 5 PM EDT. A DEEP LAYERED TROUGH THAT
GOES FROM THE GREAT LAKES TO THE NW PORTION OF THE GULF
SUPPORTS THIS FRONTAL SYSTEM. THIS FRONT AND ACCOMPANYING
THUNDERSTORM ACTIVITY WILL CONTINUE TO MOVE OUT OF THE GULF THIS
AFTERNOON REACHING THE YUCATAN CHANNEL AND WESTERN CUBA LATE
TODAY. COLD AIR STRATOCUMULUS CLOUDS AND MODERATE TO STRONG NW
WINDS OF 20 TO 30 KT WITH SOME GUSTY GALE FORCE ARE FOUND BEHIND
THE FRONT. EARLIER QUIKSCAT PASS SHOWED ISOLATED WIND BARS OF 35
TO 40 KT OVER THE NE CORNER OF THE GULF. WINDS OF SIMILAR SPEEDS
ARE BLOWING AHEAD OF THE FRONT REACHING GALE FORCE OVER THE W
ATLC. DRY AIR IS MOVING IN OVER THE NW GULF IN THE WAKE OF THE
FRONTAL PASSAGE WHICH IS CLEARING THE SKIES AS HIGH PRESSURE
CONTINUES TO BUILD ACROSS THE CENTRAL US INTO THE GULF ANCHORED
BY A 1024 MB HIGH OVER THE DEEP SOUTH.

CARIBBEAN SEA...
BROAD UPPER LEVEL RIDGE ANCHORED ON A HIGH LOCATED JUST SOUTH
JAMAICA COVERS THE BASIN. THIS IS GIVING THE W CARIBBEAN S TO SW
UPPER FLOW. THESE WINDS ARE ADVECTING TROPICAL MOISTURE OVER
CENTRAL AMERICA AND THE YUCATAN PENINSULA GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS OVER THE YUCATAN CHANNEL/NW
CARIBBEAN. HIGH SURFACE PRESSURE OVER THE W ATLC IS BUILDING SW
OVER THE CARIBBEAN ENHANCING THE MODERATE/STRONG EASTERLY TRADE
WINDS. TYPICAL PATCHES OF LOW LEVEL MOISTURE ARE MOVING WWD FROM
THE NORTH TROPICAL ATLC INTO THE E CARIBBEAN. THE SAN JUAN
DOPPLER RADAR SHOWS AFTERNOON HEAT INDUCED SHOWERS AND TSTMS
OVER THE CORDILLERA CENTRAL.

ATLANTIC OCEAN...
BROAD UPPER RIDGE ANCHORED IN THE CARIBBEAN COVERS THE W ATLC W
OF 60W. SURFACE RIDGE IS BUILDING SW OVER W ATLC ANCHORED BY A
1019 MB HIGH LOCATED NEAR 31N66W. DEEP LAYERED TROUGH IS OVER
THE CENTRAL ATLC WITH  THE AXIS THE AXIS EXTENDING SW INTO THE
DEEP TROPICS NEAR 12N56W. A COLD FRONT/SURFACE TROUGH ARE
ASSOCIATED WITH THIS UPPER FEATURE. THE SFC TROUGH RUNS FROM
31N40W TO 20N57W WITH A NARROW BAND OF LOW/MID CLOUDS AND
SCATTERED SHOWERS. A RIDGE COVERS THE REMAINDER OF THE E ATLC
WITH THE AXIS ALONG 30W. DEEP LAYERED TROUGH CROSSES THE
MADEIRA/CANARY ISLANDS WITH A DYING COLD FRONT JUST WEST OF
THESE ISLANDS. DRY AIR REMAINS IN PLACE OVER MUCH OF THE ATLC
GIVING THE AREA FAIR WEATHER CLOUDS AND LITTLE CHANCE OF
SHOWERS. ALOFT...WLY WINDS OF 50 TO 70 KT ARE TRANSPORTING UPPER
LEVEL MOISTURE FROM N SOUTH AMERICA ALL THE WAY ENE ACROSS THE
CAPE VERDE ISLANDS INTO W AFRICA.

$$
GR






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