[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 222332
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE JAN 22 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 5N5E 4N10W 2N30W CROSSING THE
EQUATOR NEAR 42W TO 1S47W. SCATTERED MODERATE CONVECTION IS S OF
2N W OF 35W.

...DISCUSSION...
GULF OF MEXICO...
A SFC TROUGH HAS BEEN NEARLY STATIONARY OVER THE PAST 24 HOURS
IN THE CENTRAL GULF ALONG 89W. VIS IMAGES SHOW A NARROW
ELONGATED N-S ENVELOPE OF LOW-LEVEL TURNING ASSOCIATED WITH THIS
BOUNDARY. SHIP/BUOY OBS CLOSELY MATCH THE SATELLITE PRESENTATION
...INDICATIVE OF CYCLONIC TURNING AT THE SFC. A WEAK 1017 MB LOW
HAS BEEN ADDED ALONG THE TROUGH AT 21Z NEAR 26N89W BETWEEN NW
WINDS REPORTED AT BUOY 42001 AND SE WINDS OBSERVED BY SHIP KRPB
AND A BUNCH OF OTHERS FARTHER N AND E. LIGHTNING AND 88-D DATA
INDICATE SCATTERED SHOWERS AND TSTMS WITHIN 180 NM E OF THE
TROUGH AXIS...SHEARED OFF BY STRONG UPPER WLY WINDS. MULTILAYER
CLOUDINESS...ISOLATED SHOWERS AND TSTMS COVER THE REMAINDER OF
THE E GULF AND SOUTH FLORIDA. A PLUME OF PACIFIC HIGH LEVEL
CLOUDINESS IS MOISTENING THE UPPER ENVIRONMENT ACROSS THE W
GULF. THIS WILL LIKELY SPREAD OVER MOST OF THE AREA THROUGH
TOMORROW.

LITTLE SIGNIFICANT CHANGE IS EXPECTED UNTIL A FRONT ENERGIZES
IN THE NW GULF WED NIGHT AND SWEEPS THROUGH THE REGION BY LATE
THU/EARLY FRI. COOLER AND DRIER AIRMASS...ADVECTED BY STRONG NLY
WINDS...IS EXPECTED BEHIND THE FRONT.

CARIBBEAN SEA...
THIS REGION IS NOTICEABLY DRIER THAN IT WAS YESTERDAY AT THIS
TIME AS THE SFC TROUGH THAT WAS IN THE NW CARIB HAS NOW SHIFTED
W OVER THE YUCATAN PENINSULA AND THE STREAM OF LOW-LEVEL
MOISTURE IN THE E CARIB HAS SAGGED S MAINLY OVER THE NRN
PORTIONS OF SOUTH AMERICA. THIS HAS ALLOWED THE TYPICAL PATCHY
LOW-LEVEL CLOUDINESS AND EMBEDDED QUICK MOVING SHOWER REGIME TO
RESUME. TRADES ARE FAIRLY BRISK...20-25 KT...E OF 80W EXCEPT TO
30 KT NEAR THE COAST OF COLOMBIA AS EVIDENT IN A RECENT ASCAT
PASS. WIDESPREAD SUBSIDENCE UNDER MAINLY ZONAL FLOW ALOFT IS
CAPPING THE LOW-LEVEL MOISTURE PROVIDING AN OVERALL NICE
EVENING. THE ONLY EXCEPTION IS OVER CENTRAL/WRN CUBA AND THE
YUCATAN CHANNEL WHERE MULTILAYER CLOUDS/SHOWERS LINGER
ASSOCIATED WITH FEATURES N OF THE REGION.

ATLANTIC...
FRONTAL BOUNDARY CONTINUES VERY SLOW SE PROGRESS FROM 32N41W TO
27N55W THEN STATIONARY OR SLOWLY LIFTING TO THE NRN BAHAMAS NEAR
27N77W. MULTILAYER CLOUDINESS AND SCATTERED SHOWERS ARE WITHIN
180 NM BEHIND THE FRONT. LIGHTNING DATA SHOWS AN AREA OF
SCATTERED TSTM ACTIVITY FROM 26N-28N BETWEEN 70W-73W WHERE A
WEAK UPPER SHORTWAVE IS ADDING INSTABILITY. WIDESPREAD ZONAL TO
SW FLOW ALOFT LIES ELSEWHERE ABOVE THE AREA W OF 60W...PROVIDING
LITTLE SUPPORT FOR THE AFOREMENTIONED FRONT.

MOST OF THE CENTRAL ATLC LIES BENEATH MODEST MID TO UPPER
RIDGING AND ABUNDANT SUBSIDENCE PROVIDING WIDESPREAD FAIR
WEATHER. MAIN FEATURE IN THE E ATLC IS A DEEP LAYER CUT OFF LOW
WITH WV IMAGES SHOWING THE UPPER CENTER NEAR 30N29W. THE SFC
CENTER CONTINUES TO DIVE S CENTERED NEAR 25N33W ANALYZED 1010
MB. ONLY LOW TO MID LEVEL CLOUDS ARE ROTATING AROUND THE SFC
CENTER...EXCEPT NEWLY DEVELOPED PATCHY SHOWERS AND TSTMS NE OF
THE LOW N OF 28N BETWEEN 27W-31W. DEEPER MOISTURE LIES
FARTHER NE N OF 27N BETWEEN 15W-26W IN AN UPPER DIFFLUENT ZONE.
A SWLY JET BRANCH LIES OVER THE TROPICS FROM 5N49W THRU THE SRN
CAPE VERDE ISLANDS TO THE COAST OF AFRICA NEAR 20N16W.
DIFFLUENCE ALOFT TO THE E OF THE JET AXIS IS ADVECTING A PLUME
OF MID TO HIGH LEVEL MOISTURE AND ENHANCING CONVECTION IN THE
ITCZ W OF 35W.

$$
CANGIALOSI




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