[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161739
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE OCT 16 2007

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 34W/35W S OF 20N MOVING W 10 KT OVER THE
PAST 24 HOURS. THIS WAVE HAS BECOME MORE ACTIVE TODAY AS IT NOW
LIES IN AN UNSTABLE ENVIRONMENT JUST E OF THE BASE OF A SHARP
UPPER TROUGH. DESPITE THE INCREASE IN ACTIVITY...THE OVERALL
ORGANIZATION HAS NOT IMPROVED MUCH AS IT REMAINS STRETCHED TO
THE NE BY STRONG UPPER SWLY WINDS. SCATTERED SHOWERS AND TSTMS
ARE WITHIN 240 NM E OF THE WAVE N OF 10N. A LARGE AREA OF
SCATTERED MODERATE CONVECTION EXISTS NEAR THE INTERSECTION OF
THE ITCZ FROM 4N-10N BETWEEN 24W-44W.

LOW AMPLITUDE TROPICAL WAVE IS ALONG 55W/56W S OF 14N MOVING W
10-15 KT. THIS WEAK WAVE HAS CHANGED LITTLE OVER THE PAST 24
HOURS ONLY CONSISTING OF CYCLONIC TURNING IN THE LOW-LEVEL CLOUD
FIELD.

TROPICAL WAVE IS OVER PORTIONS OF CENTRAL AMERICA ALONG 87W S OF
20N MOVING W 10-15 KT. THE WEAK LOW THAT HAS BEEN ON THIS WAVE
IS NO LONGER EVIDENT. IN FACT...THE WAVE ITSELF IS DIFFICULT TO
LOCATE AS THE LOW-LEVEL FLOW IS BEING AFFECTED BY THE
WELL-DEFINED TROUGHING IN THE GULF OF MEXICO. SHOWERS AND TSTMS
ARE ISOLATED OVER CENTRAL AMERICA.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 9N31W 6N48W 6N58W. THERE IS
NO SIGNIFICANT CONVECTION OUTSIDE OF THE ACTIVITY ASSOCIATED
WITH THE TROPICAL WAVE ALONG 34W/35W.

DISCUSSION...

GULF OF MEXICO...
AN AREA OF LOW PRES...ANALYZED 1007 MB...IS CENTERED IN THE SW
GULF NEAR 23N94W. THIS LOW LIES AT THE BASE OF A TROUGH WHICH
EXTENDS NORTHEASTWARD TO THE FLORIDA PANHANDLE ALONG 26N93W
31N86W. THE LOW ITSELF IS WELL DEFINED ON VISIBLE IMAGES AND IN
THE BUOY DATA. HOWEVER...SHOWERS AND TSTMS ARE LIMITED NEAR THE
SYSTEM. ACTIVITY IS MORE NUMEROUS TO THE NE OF THE LOW WITHIN
120 NM E OF THE TROUGH AXIS S OF 27N. TSTM ACTIVITY IS STRONGEST
N OF 27N WITHIN 180 NM E OF THE TROUGH. DOPPLER RADAR SHOWS THIS
MOISTURE MOVING OVER PARTS OF THE FLORIDA PANHANDLE AND EXTREME
SE ALABAMA. LOW-LEVEL CONVERGENCE NEAR THE TROUGH COUPLED WITH
DIFFLUENCE ALOFT...BETWEEN A SHORTWAVE TROUGH OVER THE NW GULF
AND UPPER HIGH NEAR CUBA...ARE THE FORCING ELEMENTS. THERE IS
POTENTIAL FOR SOME DEVELOPMENT TODAY OR TOMORROW BEFORE THE
UPPER-LEVEL WINDS BECOME UNFAVORABLE IN THE AREA AS THIS SYSTEM
MOVES NORTHWESTWARD TO NORTHWARD. THE REMAINDER OF THE GULF IS
RELATIVELY QUIET.

CARIBBEAN SEA...
AN UPPER LOW CONTINUES TRACKING WNW CENTERED TO THE NNW OF
COLOMBIA NEAR 15N77W. FAIRLY STRONG S TO SE WINDS ALOFT ON THE E
SIDE OF THE LOW IS ADVECTING ABUNDANT TROPICAL MOISTURE INTO THE
REGION BETWEEN 65W-72W. MUCH OF THIS MOISTURE IS IN THE FORM OF
MID-HIGH LEVEL CLOUDINESS...THOUGH AN AREA OF SCATTERED SHOWERS
AND TSTMS EXIST FROM 15N-18N BETWEEN 66W-71W. THE MIMIC TPW
ANIMATION SUGGESTS THAT A WEAK TROPICAL WAVE MAY BE IN THIS AREA
ENHANCING THIS SHOWER ACTIVITY. MUCH DRIER AIR IS BEING DRAWN IN
FROM THE TROPICAL ATLC ACROSS THE LESSER ANTILLES PROVIDING
TRANQUIL WEATHER. THE WRN HALF OF THE CARIBBEAN IS EXPERIENCING
MAINLY FAIR WEATHER UNDER NELY UPPER FLOW BESIDES FOR THE FEW
SHOWERS OVER CENTRAL AMERICA ASSOCIATED WITH THE WEAK TROPICAL
WAVE AND ITCZ RELATED ACTIVITY S OF 12N. TRADE WINDS ARE MAINLY
MODERATE AND ARE EXPECTED TO REMAIN THAT WAY OVER THE NEXT
COUPLE OF DAYS.

ATLANTIC OCEAN...
A SERIES OF FRONTAL BOUNDARIES ARE MOVING ACROSS THE WESTERN
ATLANTIC. ONE OF THESE FRONTS CROSSES INTO OUR DISCUSSION AREA
ALONG 32N43W AND EXTENDS TO 28N52W. THIS BOUNDARY WAS NEARLY
STATIONARY FROM THE BAHAMAS EASTWARD OVER THE PAST FEW DAYS.
HOWEVER...BASED ON TODAY'S DATA THE FRONT HAS MOSTLY DISSIPATED
IN THE AREA EXCEPT FOR A WEAK LOW-LEVEL TROUGH ALONG 73W WHICH
APPEARED TO BREAK OFF FROM THE MAIN BOUNDARY AND IS MOVING W
WITH THE LOW-LEVEL FLOW. ISOLATED SHOWERS AND TSTMS ARE LOCATED
WITHIN 300 NM E OF THE TROUGH AXIS. HIGH LEVEL CLOUDS ARE SPREAD
NE FROM THERE CONTAINED N OF 28N W OF 44W. WIDESPREAD STRONG
SUBSIDENCE DOMINATES THE AREA W OF 80W...EXCEPT FOR THE W
BAHAMAS WHERE THERE APPEARS TO BE A SMALL SCALE MID-LEVEL TROUGH
DEVELOPING. SFC WINDS ARE NOT AS STRONG AS THE PAST COUPLE OF
DAYS DUE TO THE WEAKENING PATTERN.

CONDITIONS ARE FAIRLY TRANQUIL ACROSS MUCH OF THE REMAINDER OF
THE CENTRAL AND E ATLC. THE SFC PATTERN IS MOSTLY CONTROLLED BY
RIDGING EXTENDING S/SW FROM A 1019 MB HIGH SITUATED W OF THE
CANARY ISLANDS NEAR 29N22W. THIS IS PRODUCING MAINLY LIGHT WINDS
OVER THE SUBTROPICAL E AND CENTRAL ATLC...WHILE MODERATE TRADES
PERSIST IN THE TROPICS ESPECIALLY NEAR THE LARGE TROPICAL WAVE.
THE UPPER PATTERN OVER THE E ATLC CONSISTS OF A LARGE SCALE
HIGHLY AMPLIFIED ELONGATED UPPER RIDGE/TROUGH PATTERN. A SWLY
JET BRANCH ORIGINATES JUST AHEAD OF THE BASE OF THE TROUGH OVER
THE TROPICAL ATLC AND EXTENDS NE TO AFRICA ALONG 12N38W 24N16W.
THIS JET IS PROVIDING ENERGY BUT SHEARING THE TROPICAL WAVE
ALONG 34W/35W AND SPREADING HIGH LEVEL CLOUDINESS ACROSS THE
TROPICAL E ATLC.

$$
CANGIALOSI


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