[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 152323
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 5N9W 1N20W EQ30W CROSSING THE EQ
NEAR 40W INTO NE BRAZIL NEAR 1S46W. SCATTERED MODERATE
CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN
14W-17W AND 26W-32W.

...DISCUSSION...

GULF OF MEXICO...
A MUCH COLDER AND DRIER AIRMASS HAS NOW SETTLED IN AS THE STRONG
COLD FRONT HAS PUSHED THROUGH. A FAIRLY TIGHT PRES GRADIENT
BETWEEN A MODERATE HIGH PRES RIDGE OVER TEXAS AND ERN MEXICO AND
A RAPIDLY DEEPENING LOW PRES SYSTEM IN THE MID-ATLANTIC STATES
IS PRODUCING STRONG N-NWLY WINDS IN THE GULF ESP E OF 90W. THESE
WINDS ARE PRODUCING SEAS IN THE 8 TO 14 FT RANGE. WIDESPREAD
BROKEN COLD AIR STRATOCUMULUS CLOUDS ARE CLEARLY SEEN ON SAT
IMAGES INDICATING THE COLD AIR. THE ONLY AREA OF THICKER LOW
CLOUDS IS OVER THE HIGH TERRAIN OF THE LOWER SIERRA MADRE
MOUNTAINS IN MEXICO WHERE THE TAIL END OF THE STATIONARY FRONT
IS STILL HUNG UP. IN THE MID AND UPPER LEVELS...CONFLUENCE ON
THE S SIDE OF AN UPPER TROUGH IS PROVIDING ABUNDANT SUBSIDENCE N
OF 25N. ELSEWHERE SCATTERED HIGH CLOUDS ARE FILTERING IN BY S
AND SWLY UPPER FLOW BETWEEN A STRONG RIDGE IN THE CARIB AND A
SHARP SHORTWAVE TROUGH OVER NRN BAJA. OVER THE NEXT COUPLE OF
DAYS...WINDS AND SEAS WILL SUBSIDE AS HIGH PRES MOVES E
CENTERING ITSELF ACROSS THE AREA LATE MON AND TUES.

CARIBBEAN SEA...
THE STRONG COLD FRONT HAS JUST ENTERED THE NW CARIB EXTENDING
FROM THE FL KEYS ACROSS WRN CUBA TO THE YUCATAN PENINSULA ALONG
24N81W 20N86W 17N91W.  A NARROW LINE...ABOUT 90 NM....OF SHOWERS
AND TSTMS ARE AHEAD OF THE FRONT N OF 20N WITH THE STRONGEST
ACTIVITY OVER WRN CUBA AND THE NEARBY WATERS AS CLOUD TOP TEMPS
ARE APPROACHING -80 C. THIS FRONT HAS BROUGHT MUCH COOLER AIR TO
THE NRN YUCATAN WITH TEMPS AT LEAST 20 F DEG COOLER THAN
YESTERDAY AT THIS TIME. THE REMAINDER OF THE REGION CONTINUES
ITS TRANQUIL WEATHER UNDER THE INFLUENCE OF A STRONG UPPER HIGH
CENTERED NEAR 16N72W AND ABUNDANT DRY STABLE AIR ALOFT. THE
TRADES ARE LIGHT TO MODERATE ACROSS MUCH OF THE AREA DUE TO THE
WEAK PRES GRADIENT. HOWEVER...BEHIND THE FRONT N-NW WINDS
INCREASE TO 20-25 KT ADVECTING IN THE COOLER AIRMASS. OVER THE
NEXT COUPLE OF DAYS...THE FRONT IS EXPECTED TO PUSH E AND SLOWLY
WEAKEN. WHILE THE CONVECTIVE ACTIVITY SHOULD BECOME LESS OF AN
ISSUE...A FAIR AMOUNT OF LOW-LEVEL MOISTURE WILL LIKELY LINGER
IN THE VICINITY OF THE FRONT.

WESTERN ATLANTIC...
A STRONG COLD FRONT...ASSOCIATED WITH A RAPIDLY DEEPENING LOW
PRES SYSTEM OVER THE MID-ATLANTIC STATES...IS PUSHING E ACROSS
THE EXTREME WRN ATLC FROM THE CAROLINA COASTLINE ACROSS S
FLORIDA/THE STRAITS AND INTO THE NW CARIB. A SWATH OF SHOWERS
AND TSTMS ARE WITHIN 90-120 NM AHEAD OF THE FRONT. THE STRONGEST
ACTIVITY IS IN THE NW CARIB...REFER TO THE CARIB SECTION FOR
DETAILS. THE BIGGEST STORY IS PROBABLY THE STRONG WINDS BOTH
AHEAD AND BEHIND THE FRONT. A GALE WARNING IS IN EFFECT N OF 27N
FROM 75W TO THE FRONT FOR SLY WINDS IN THE 30-40 KT RANGE. THE W
TO NW WINDS BEHIND THE FRONT ARE ALMOST AS STRONG...30-35 KT.
THESE VERY BRISK WINDS ARE BUILDING HAZARDOUS SEAS IN THE AREA.
THE REMAINDER OF THE REGION...W OF 60W...IS COVERED BY
VERTICALLY STACKED RIDGING. THE MID/UPPER LEVEL RIDGE AXIS
EXTENDS FROM A STRONG ANTICYCLONE IN THE CARIB NWD ALONG 21N72W
32N69W. THE SFC HIGH IS ANALYZED 1020 MB NEAR BERMUDA. BESIDES
FOR DEBRIS CIRRUS BEING ADVECTED E BY THE UPPER WLYS...THE
REGION IS FREE OF ORGANIZED CLOUD COVER. THE FRONT IS EXPECTED
TO CONTINUE ITS RATHER QUICK EWD PROGRESSION OVER THE NEXT FEW
DAYS. WINDS SHOULD REMAIN STRONG AHEAD AND BEHIND THE FRONT AS
LOW PRES DEEPENS AND MOVES SLOWLY OFF THE MID-ATLANTIC COAST.

CENTRAL AND EASTERN ATLANTIC...
A VERTICALLY STACKED TROUGH/RIDGE PATTERN IS ESTABLISHED ACROSS
THIS REGION. A 997 MB LOW PRES SYSTEM LOCATED WELL N OF THE AREA
NEAR 41N44W HAS A WEAK DISSIPATING FRONT/REMNANT THAT ENTERS THE
AREA NEAR 32N36W AND CONTINUES SW TO 21N56W. THIS BOUNDARY IS
NOTHING MORE THAN A NARROW LINE OF LOW CLOUDS INDICATING A
RATHER PRONOUNCED WIND SHIFT. THE UPPER AXIS IS HIGHLY ELONGATED
EXTENDING ALONG 32N39W 20N55W 9N60W. THE ASSOCIATED DEEPEST
MOISTURE...WHICH IS LIKELY IN THE FORM OF SCATTERED SHOWERS ARE
MOSTLY CONTAINED W OF THE AXIS N OF 27N BETWEEN 50W-55W. FARTHER
E...A MODEST RIDGE IS IN CONTROL. THE MID/UPPER AXIS RUNS FAIRLY
N-S ALONG 29W WITH A PAIR OF SFC HIGHS BENEATH IT ANALYZED 1021
MB NEAR 31N28W AND 1020 MB NEAR 24N34W. THIS HIGH PRES...BOTH AT
THE SFC AND ALOFT...IS ALLOWING FAIR WEATHER TO PREVAIL ACROSS
NEARLY THE ENTIRE AREA. NWP MODELS SHOW THIS RIDGE FLATTENING
OVER THE NEXT DAY OR TWO IN RESPONSE TO LOW PRES TO ITS W.

$$
CANGIALOSI








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