[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 270526
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST MON NOV 27 2006

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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N12W 5N30W 6N45W 4N54W. SCATTERED
MODERATE CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE AXIS E
OF 21W. THE REMAINDER OF THE AXIS IS RATHER QUIET WITH ONLY
PATCHES OF ISOLATED MODERATE FROM 4N-8N BETWEEN 25W-34W.

...DISCUSSION...
THE GULF OF MEXICO...
THE WEATHER ACROSS THE GULF REMAINS FAIRLY UNEVENTFUL AS SFC
HIGH PRES CONTINUES TO DOMINATE THE AREA. BREEZY 15-20 KT NE TO
E WINDS IN THE ERN AND CNTRL GULF IS ADVECTING SOME LOW-LEVEL
CLOUDS AND ISOLATED SHOWERS ACROSS CENTRAL AND SOUTH FLORIDA ON
THE BREEZE WITH SOME BROKEN CLOUDS PUSHING W ACROSS THE GULF
WATERS. HOWEVER BECAUSE OF THE WIDESPREAD STRONG SUBSIDENCE
ABOVE THE LOW-LAYER OF MOISTURE THERE IS LIMITED DEPTH TO THE
CLOUDS. THE SFC FLOW IS A LITTLE LIGHTER AND IS MORE ESELY IN
THE WRN GULF FLOWING CLOCKWISE AROUND THE SFC HIGH. IN THE UPPER
LEVELS...A PRONOUNCED RIDGE EXTENDS FROM THE EPAC ACROSS SRN
MEXICO INTO THE CENTRAL GULF. SLIGHT UPPER TROUGHING IS LIFTING
OUT BUT STILL LIES ABOVE FLORIDA. GFS SHOWS THE UPPER AND SFC
RIDGE BUILDING E. THIS SHOULD ALLOW TEMPS TO REMAIN SLIGHTLY
ABOVE NORMAL VALUES OVER THE NEXT FEW DAYS. THE NEXT AIRMASS
CHANGE IS ANTICIPATED TO AFFECT THE AREA LATE IN THE WEEK AS A
POTENTIAL STRONG COLD FRONT APPROACHES THE NW PORTION ON THU.

THE CARIBBEAN SEA...
THE UNSETTLED WEATHER THAT HAS BEEN IN THE SW CARIBBEAN OVER THE
PAST SEVERAL DAYS...ASSOCIATED WITH A NEARLY STATIONARY SFC LOW
PRES TROUGH ALONG 77W FROM 10N-17N...HAS DIMISHED. THE FEATURE
IS STILL EVIDENT BUT IS NOW VERY SHALLOW WITH ONLY LOW TO
MID-LEVEL CLOUDS ROTATING ABOUT THE AXIS. THE TAIL END OF A
SLOWLY WEAKENING STATIONARY FRONT EXTENDS ACROSS THE WINDWARD
PASSAGE TO JUST W OF JAMAICA NEAR 18N76W. DEEP MOISTURE IS VERY
LIMITED ALONG THE FRONT WITH ONLY ISOLATED SHOWERS WITHIN 120 NM
OF THE SFC BOUNDARY. A VERY BROAD FLAT UPPER LEVEL
RIDGE...CENTERED OVER VENEZUELA...IS ADVECTING SOME MOISTURE
FROM THE ITCZ AND SPREADING IT ABOVE THE SFC FRONT INTO THE
ATLC. HOWEVER...AS MENTIONED...THE MOISTURE IN THE AREA IS
NOTICEBLY THINNER THAN IT HAS BEEN WITH ONLY BROKEN MID-HIGH
LEVEL CLOUDINESS AND EMBEDDED ISOLATED SHOWERS NOTED BETWEEN
72W-83W. VERY DRY AIR/STRONG SUBSIDENCE LIES ABOVE THE ERN AND
THE EXTREME WRN CARIB SUPPRESSING ANY DEEP CLOUDINESS. TRADES
ARE MODERATE AND WILL LIKELY REMAIN THAT WAY OVER THE NEXT
COUPLE DAYS. LATER THIS WEEK...THESE WINDS WILL LIKELY INCREASE
AS THE FRONTAL BOUNDARY PULLS NE AND WEAKENS AND STRONG HIGH
PRES DEVELOPS TO THE N.

THE ATLANTIC OCEAN...
WEAK UPPER TROUGHING...VERY DRY AIR ALOFT AND PATCHES OF
LOW-LEVEL MOISTURE UNDERNEATH THE STRONG MID-LEVEL CAP COVERS
THE AREA W OF A PERSISTENT FRONTAL BOUNDARY IN THE CNTRL/WRN
ATLC. THE FRONT IS ASSOCIATED WITH AN OCCLUDED 1014 MB LOW NEAR
32N58W AND IS PROGRESSIVE...COLD FRONT...ALONG 32N55W 27N59W
THEN STATIONARY TO THE WINDWARD PASSAGE. MULTILAYERED CLOUDS
WITH EMBEDDED SCATTERED SHOWERS ARE ASSOCIATED WITH THE WEAK
LOW/FRONTAL BOUNDARY AND EXTEND WITHIN 240 NM E OF THE FRONT N
OF 27N AND WITHIN 150 NM EITHER SIDE S OF 27N. A SHORTWAVE UPPER
TROUGH STRETCHES FROM 32N30W 23N41W TO AN UPPER LOW IN THE DEEP
TROPICS NEAR 9N53W. ELONGATED RIDGING LIES E OF THE SHORTWAVE
AND COVERS THE REMAINDER OF THE E ATLC. THIS UPPER LEVEL PATTERN
IN THE E ATLC HAS SIGNIFICANTLY FLATTENED TODAY AS THE SHORTWAVE
TROUGH HAS HELPED TO BREAK DOWN THE ONCE AMPLIFED UPPER LEVEL
RIDGE. AN UPPER LEVEL HIGH IS LOCATED IN THE TROPICAL ATLC E OF
THE UPPER LOW NEAR 9N39W. UPPER LEVEL DIFFLUENCE BETWEEN THE
UPPER LOW AND HIGH IS GENERATING ISOLATED TO SCATTERED SHOWERS
FROM 10N-17N BETWEEN 39W-52W...BUT THIS ACTIVITY IS MUCH WEAKER
THAN IT HAS BEEN THE PAST FEW DAYS DUE TO THE FLATTENING PATTERN.
PLENTY OF DRY STABLE AIR ALOFT IS LOCATED E OF 30W ENHANCED BY
UPPER LEVEL CONFLUENT FLOW. AT THE SFC...WEAK TO MODERATE HIGH
PRES RIDGING IS THE RULE ACROSS THE SUBTROPICAL ATLC SUPPORTED
BY A 1023 MB HIGH NEAR 30N22W. THIS RIDGING IS INTERRUPTED BY
THE FRONTAL BOUNDARY/WEAK LOW MENTIONED IN THE CNTRL ATLC.

$$
CANGIALOSI


This weather bulletin was brought to you by:
www.nashvilleweather.net