[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221124
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU FEB 22 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N12W 2N23W 1N34W EQ40W CROSSING THE
EQUATOR NEAR 46W AND INTO NE BRAZIL. CLUSTERS OF SCATTERED
MODERATE CONVECTION ARE WITHIN 90 NM EITHER SIDE OF THE AXIS
BETWEEN 18W-21W AND FROM THE EQ TO 4N BETWEEN 48W-51W.

...DISCUSSION...
GULF OF MEXICO...
WEAK HIGH PRES RIDGING IS THE OVERALL THEME ACROSS THE W ATLC
AND GULF WITH A 1022 MB HIGH CENTERED NEAR 29N91W. THERE ARE TWO
VERY WEAK SFC TROUGHS ANALYZED IN THE REGION. ONE OF THESE
EXTENDS FROM THE ATLC ACROSS S/CENTRAL FL TO 26N86W. THE OTHER
IS ALONG THE MEXICAN GULF COAST FROM 18N-23N. NEITHER OF THESE
LOW LEVEL TROUGHS ARE PRODUCING ANY NOTABLE WEATHER. ALOFT...THE
FLOW IS RATHER ZONAL TO WNW...SANDWICHED BETWEEN A SPRAWLING
RIDGE CENTERED OVER S MEXICO AND TROUGHING ALONG AND OFFSHORE OF
THE U.S. EAST COAST. WV IMAGES SHOW A GOOD AMOUNT OF DRY AIR
ACROSS THE ENTIRE AREA...ESPECIALLY N OF 27N AND S OF 22N CLOSER
TO THE UPPER CONFLUENT ZONES. ESSENTIALLY THIS PATTERN...BOTH
THE SFC AND ALOFT...IS LEADING TO FAIR AND MILD WEATHER ACROSS
THE REGION WITH LIGHT WINDS. OVER THE NEXT COUPLE OF DAYS...THE
SFC PATTERN IS EXPECTED TO TIGHTEN UP AS STRONG CANADIAN HIGH
PRES RIDGING EXTENDS WELL S INTO THE AREA. AS THIS HIGH SLIDES
E...SLY RETURN FLOW IS EXPECTED TO INCREASE IN THE W GULF
BEGINNING LATE FRI IN RESPONSE TO THE NEXT COLD FRONT FORECAST
TO PUSH OFF THE TX COAST ON SAT.

CARIBBEAN SEA...
A RELATIVELY TIGHT PRES GRAD...BETWEEN HIGH PRES LOCATED IN THE
SW ATLC AND LOW PRES OVER S AMERICA...IS PRODUCING MODERATE TO
STRONG TRADES ACROSS THE CENTRAL CARIB. TYPICAL PATCHES OF LOW
LEVEL MOISTURE WITH EMBEDDED SHOWERS DRIVEN BY THE TRADES ARE
AFFECTING THE AREA...PARTICULARLY THE E CARIBBEAN AND OVER THE
ISLAND OF HISPANIOLA. THE MID AND UPPER LEVEL PATTERN IS
DOMINATED BY A STRONG RIDGE CENTERED OVER S MEXICO. NEARLY ALL
OF THE REGION LIES ON THE E SIDE...DOWNWARD BRANCH...OF THE
RIDGE ENHANCING AN ABUNDANCE OF EXTREMELY DRY/STABLE AIR. THIS
STRONG CAP IS SUPPLYING THE AREA WITH FAIR WEATHER...PREVENTING
THE LOW LEVEL MOISTURE PATCHES OF ACQUIRING MUCH DEPTH. OVER THE
NEXT COUPLE OF DAYS...NWP MODELS SHOW LITTLE CHANGE IN THE
OVERALL PATTERN SO SIMILAR TRADES/WX CONDITIONS ARE ANTICIPATED.

ATLANTIC OCEAN...
THE SFC PATTERN IS DOMINATED BY A LARGE FLAT RIDGE STRETCHED
ACROSS THE ENTIRE BASIN. THERE ARE TWO EMBEDDED HIGH
CENTERS...THE STRONGER IS 1025 MB LOCATED 250 NM OR SO W OF THE
CANARY ISLANDS. THE OTHER IS 1020 MB LOCATED BETWEEN BERMUDA AND
HISPANIOLA NEAR 25N67W. THIS STRETCHED RIDGE IS FURTHER S THAN
NORMAL AND IS PRODUCING FAIR WEATHER ACROSS THE MAJORITY OF THE
DISCUSSION AREA. THE MID AND UPPER LEVEL PATTERN IS A LITTLE
MORE COMPLEX. STRONG ZONAL FLOW ALOFT COVERS MOST OF THE AREA W
OF 50W. AN UPPER DIFFLUENCE ZONE IS GENERATING A SWATH OF
MOISTURE CONFINED N OF 28N BETWEEN 42W-73W. THIS SWATH IS
QUICKLY PUSHING E BEING REPLACED BY MUCH DRIER AIR ALOFT. AN
UPPER LEVEL TROUGH DIPS TO A BASE NEAR 31N41W HELPING TO FURTHER
LIFT THE MOISTURE MOSTLY N OF 32N BETWEEN 30W-40W. THIS UPPER
TROUGH SUPPORTS A WEAK STATIONARY OR SLOW MOVING WARM FRONT
ALONG 30N32W 32N40W 26N51W 21N62W. THE FRONT IS SLOWLY BECOMING
DIFFUSE ONLY DEFINED BY BROKEN MULTILAYERED CLOUDS AND A WIND
SHIFT. IN THE TROPICAL ATLC...A WEAK UPPER TROUGH HAS DEVELOPED
ROUGHLY ALONG 20N48W 10N58W. E OF THE TROUGH AXIS...SWLY FLOW IS
ADVECTING SOME HIGH LEVEL MOISTURE NWD BETWEEN 41W-47W S OF 19N.
THIS MOISTURE THEN GETS SUPPRESSED S BY ANOTHER WEAK TROUGH
ALONG 32W S OF 18N. IN THE SUBTROPICAL E ATLC...A STRONG UPPER
LEVEL RIDGE IS IN CONTROL KEEPING CONDITIONS TRANQUIL.

$$
CANGIALOSI




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