[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221724
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU MAY 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 23W S OF 12N MOVING W 10 KT. THIS WAVE
REMAINS FAIRLY WELL DEFINED WITH VISIBLE IMAGES SHOWING
LOW-LEVEL CYCLONIC TURNING ALONG THE AXIS AND A CLEAR
PERTURBATION IN THE ITCZ. HOWEVER...MUCH OF THIS TURNING IS LOW
LATITUDE CENTERED NEAR 6N. SCATTERED SHOWERS AND TSTMS ARE
WITHIN 150 NM EITHER SIDE OF THE AXIS S OF 9N.

TROPICAL WAVE IS ALONG 56W/57W S OF 11N MOVING W 10-15 KT. THIS
WAVE IS EASY TO LOCATE TODAY AS AN INVERTED-V SHAPE IS EVIDENT
IN THE LOW-LEVEL CLOUD PATTERN. HOWEVER...CONVECTION IS
MINIMAL...LIKELY SUPPRESSED BY DRY MID-UPPER FLOW TO THE W OF A
HIGH AMPLITUDE TROUGH.

TROPICAL WAVE IS OVER PANAMA ALONG 80W S OF 12N MOVING W 10 KT.
THIS WAVE HAS BECOME VERY DIFFICULT TO TRACK AS THE S PORTION IS
NOW EMBEDDED IN STRONG SW/W LOW-LEVEL FLOW WHICH IS LEADING TO A
LARGE AREA OF CONVECTION OVER THE TROPICAL EPAC S OF PANAMA AND
COSTA RICA. SHOWERS AND TSTMS ARE LOCATED OVER THE W CARIB...BUT
THIS SEEMS MORE ASSOCIATED WITH THE UPPER PATTERN. SEE CARIBBEAN
SECTION BELOW FOR DETAILS.

..THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N10W 7N21W 2N30W 1N40W 1N50W.
SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 90 NM EITHER
SIDE OF THE AXIS E OF 13W AND WITHIN 150 NM N OF THE AXIS
BETWEEN 36W-46W.

...DISCUSSION...

GULF OF MEXICO...
STRONG SW UPPER FLOW IS STILL SET UP OVER THE REGION BETWEEN A
DEEP LAYER COMPLEX LOW OVER THE ROCKIES AND MID TO UPPER RIDGING
OVER THE CARIBBEAN. DRY AIR ALOFT IS ESTABLISHED OVER THE SW
GULF...WHERE THE FLOW IS CONFLUENT...BUT IT IS STILL FAIRLY
MOIST OVER THE E HALF DUE TO A DIFFLUENT UPPER PATTERN. IN
FACT...DOPPLER RADAR AND LIGHTNING DATA ARE DEPICTING A FAIRLY
ACTIVE AREA OF SCATTERED SHOWERS AND TSTMS OVER THE N CENTRAL
AND NE WATERS N OF 27N E OF 89W. ISOLATED ACTIVITY IS OCCURRING
FARTHER WEST N OF 28N BETWEEN 89W-95W AND OVER THE SE WATERS
NEAR THE COAST OF FLORIDA. AT THE SFC...SLY 15-20 KT WINDS ARE
FAIRLY UNIFORM ACROSS THE AREA BUILDING SEAS TO 8 FT OVER THE NW
WATERS. THESE OVERALL MOIST CONDITIONS SHOULD CONTINUE TO HOLD
UNTIL A BACK DOOR TYPE COLD FRONT DRIES OUT FLORIDA AND THE NE
WATERS LATE THIS WEEKEND AND EARLY NEXT WEEK.

CARIBBEAN SEA...
AN UPPER LOW IS SPINNING OVER THE E CARIB CENTERED NEAR 15N68W.
THIS FEATURE IS ENHANCING DRY AIR ON ITS W SIDE AND IS BARELY
MOISTENING THE UPPER LEVELS TO ITS E...AS IT IS EMBEDDED IN A
SUBSIDENT ENVIRONMENT ASSOCIATED WITH LARGE SCALE RIDGING.
SCATTERED SHOWERS AND TSTMS ARE OVER THE SW/W PORTION OF THE
BASIN FROM 12N-18N BETWEEN 78W-84W. THIS ACTIVITY IS ASSOCIATED
WITH UPPER DIFFLUENCE AND SOME INTERACTION WITH A NEARBY
TROPICAL WAVE. MORE NUMEROUS MODERATE CONVECTION LIES S OF THE
AREA OVER THE TROPICAL EPAC. QSCAT DATA FROM THIS MORNING
REVEALED SE 20 KT WINDS OVER THE NW CARIB...WHICH CONTINUE IN
THE GULF OF MEX. FAIRLY RELAXED E/SE TRADES ARE OCCURRING
ELSEWHERE.

ATLANTIC OCEAN...
A BROAD FLAT MID TO UPPER RIDGE LIES OVER THE W ATLC PROVIDING
STABLE CONDITIONS S OF 25N. HIGH LEVEL CLOUDS LIE OVER THE
REGION N OF 25N W OF 50W ASSOCIATED WITH STRONG ZONAL FLOW ON
THE N PERIPHERY OF THE RIDGE. MUCH OF THE DEEPER MOISTURE LIES
JUST N OF THE REGION ASSOCIATED WITH A FRONTAL BOUNDARY.
FARTHER E...A LARGE SCALE HIGH AMPLITUDE TROUGH HAS MOVED LITTLE
OVER THE PAST DAY OR TWO ANCHORED BY AN UPPER LOW NEAR 30N39W
AND EXTENDS SSW TO 2N45W. UPPER LEVEL DIFFLUENCE AND STRONG SW
FLOW ALOFT...BETWEEN THE UPPER TROUGH AND AN UPPER HIGH OVER W
AFRICA...IS SPREADING HIGH LEVEL CLOUDINESS ACROSS THE E ATLC.
SCATTERED SHOWERS ARE POSSIBLE ALONG AND JUST W OF THE TROUGH
AXIS FROM 16N-22N BETWEEN 40W-46W.

AT THE SFC...A QUASI-STATIONARY 1025 MB HIGH CENTERED NEAR
33N39W IS PROVIDING MODERATE NE/E TRADES ACROSS THE TROPICS AND
MAINLY LIGHT WINDS ACROSS THE SUBTROPICS. HOWEVER...THE
EXCEPTION TO THIS IS ON ITS NW PERIPHERY N OF 28N BETWEEN 55W
AND 75W WHERE STRONG SW WINDS EXIST IN RESPONSE TO A LOW PRES
SYSTEM OVER THE N ATLC.

$$
CANGIALOSI/BELL




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