[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 092359
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT NOV 09 2013

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH PASSES ACROSS COASTAL SENEGAL NEAR 13N17W TO
12N18W. THE ITCZ CONTINUES FROM 12N18W TO 7N20W TO 5N30W TO THE
COAST OF N BRAZIL AT 4N51W. SCATTERED MODERATE CONVECTION IS
FROM 2N-7N BETWEEN 25W-52W.

...DISCUSSION...

GULF OF MEXICO...

AS OF 2100 UTC...THE TAIL END OF A COLD FRONT EXTENDS FROM S
FLORIDA AT 26N80W TO THE SE GULF OF MEXICO AT 25N85W. A SHEAR
LINE CONTINUES TO THE BAY OF CAMPECHE ALONG 24N90W 19N94W.
SCATTERED MODERATE CONVECTION IS OVER THE SE GULF FROM 23N-25N
BETWEEN 84W-86W. SCATTERED SHOWERS ARE WITHIN 90 NM OF THE
REMAINDER OF THE FRONT AND SHEAR LINE. A 1024 MB HIGH IS
CENTERED OVER SOUTH CAROLINA WITH A RIDGE AXIS TO E TEXAS. IN
THE UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED OVER THE NW
CARIBBEAN NEAR 20N85W PRODUCING ANTICYCLONIC FLOW OVER THE GULF.
EXPECT OVER THE NEXT 24 HOURS FOR SCATTERED SHOWERS TO PERSIST
OVER THE BAY OF CAMPECHE...YUCATAN PENINSULA ...AND W CUBA.

CARIBBEAN SEA...

A SURFACE TROUGH IS OVER THE W CARIBBEAN FROM 18N82W TO PANAMA
AT 9N80W. ISOLATED MODERATE CONVECTION IS OVER THE W CARIBBEAN
AND CENTRAL AMERICA W OF 76W. A MONSOON TROUGH ALSO EXTENDS FROM
E PANAMA TO NW COSTA RICA TO EL SALVADOR ENHANCING CONVECTION.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE INLAND OVER N
COLOMBIA AND N VENEZUELA. SCATTERED SHOWERS ARE OVER THE HIGHER
ELEVATIONS OF PUERTO RICO...HISPANIOLA...JAMAICA...AND CUBA. IN
THE UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED OVER THE NW
CARIBBEAN NEAR 20N85W. AN UPPER LEVEL LOW IS CENTERED OVER THE
SW CARIBBEAN NEAR 14N80W ENHANCING THE CONVECTION OVER THE SW
CARIBBEAN. IN CONTRAST RIDGING IS PRODUCING NORTHERLY FLOW OVER
THE E CARIBBEAN E OF 70W WITH STRONG SUBSIDENCE. EXPECT OVER THE
NEXT 24 HOURS FOR CONVECTION TO PERSIST OVER THE W CARIBBEAN AND
CENTRAL AMERICA W OF 80W.

...HISPANIOLA...

PRESENTLY SCATTERED SHOWERS ARE OVER THE HIGHER ELEVATIONS OF
HISPANIOLA DUE TO THE TRADEWIND FLOW. STRONG SUBSIDENCE IS OVER
THE ISLAND AND IS FORCAST TO PERSIST OVER THE NEXT 24 HOURS.
EXPECT LITTLE CHANGE OVER THGE NEXT 24 HOURS.

ATLANTIC OCEAN...

A COLD FRONT EXTENDS FROM THE CENTRAL ATLANTIC AT 32N54W TO
27N63W TO 26N70W TO S FLORIDA AT 26N 80W. SCATTERED SHOWERS ARE
WITHIN 90 NM OF THE FRONT. A 1034 MB HIGH IS CENTERED OVER TH

000
FXUS64 KBRO 092359 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
559 PM CST SAT NOV 9 2013

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE
WIDESPREAD LOW TO MID LEVEL CLOUDS ACROSS DEEP SOUTH TEXAS AND THE
RIO GRANDE VALLEY THIS EVENING. CEILINGS WERE AROUND 5000FT ACROSS
THE AREA WITH HIGHER CEILINGS AT KAPY AND KSPL. VFR CONDITIONS AND
LIGHT EASTERLY WINDS BECOMING VARIABLE THIS EVENING. LATER
TONIGHT...LOW LEVEL MOISTURE WILL INCREASE WITH LOWER CLOUDS
FORMING ACROSS THE AREA. MVFR CEILINGS ARE POSSIBLE AT VALLEY AREA
TAF SITES WITH THE BEST CHANCE BEING AT KMFE BASED ON POINT
SOUNDINGS AND SHORT TERM MODELS WITH TIMING AROUND 09-15Z. MVFR
CEILINGS COULD LINGER INTO THE LATER MORNING HOURS ON SUNDAY.
LIGHT TO MODERATE NORTHEAST WINDS EXPECTED ACROSS THE AREA ON
SUNDAY.

&&

.PREV DISCUSSION... /ISSUED 319 PM CST SAT NOV 9 2013/

SHORT TERM.../NOW THROUGH SUNDAY NIGHT/...WEAK MID LEVEL SHORTWAVE
TROUGH MOVING ACROSS NORTHERN MEXICO ATTM WITH A PLUME OF MID LEVEL
MOISTURE AND A FINGER OF THE 250MB JET AHEAD OF IT. A FEW RETURNS ON
THE RADAR HAVE APPEARED ACROSS THE EXTREME NORTHERN PORTIONS OF THE
AREA BUT WITH DRY AIR AT 850-800MB AS SEEN ON KBRO AND KCRP 12Z
SOUNDINGS...THIS IS PROBABLY NOT REACHING THE GROUND. TEMPERATURES
HAVE WARMED NICELY TODAY INTO THE 70S SO FAR THROUGH EARLY AFTERNOON
DESPITE MOSTLY CLOUDY SKIES. WINDS WILL REMAIN LIGHT TODAY FROM THE
EAST.

SFC HIGH PRESSURE RIDGING WILL LOSE ITS GRIP THROUGH THE PERIOD AS
COASTAL TROUGHING STRENGTHENS ACROSS THE WESTERN GULF OF MEXICO.
MOISTURE WILL START TO RETURN AND MAY BECOME ADAQUATE ENOUGH FOR
COASTAL SHOWERS SUNDAY AND SUNDAY NIGHT AS THE COASTAL WATERS COMES
UNDER INCREASING INFLUENCE OF THE COASTAL TROUGHING. CLOUDS WILL
INCREASE WITH THE INCREASE IN LOW LEVEL MOISTURE WHICH WILL LEAD TO

****ERROR: INCOMPLETE DATA

NTO SATURDAY.

MOISTURE AHEAD OF THE CANADIAN COLD FRONT IS PRETTY LIMITED SO
BOTH THE ECMWF AND GFS POPS HAVE BACKED OFF SOMEWHAT VERSUS THE
WETTER PREVIOUS RUNS. SOME BETTER MOISTURE ADVECTION OCCURS AHEAD
OF THE 2ND 500 MB TROUGH AXIS DIGGING ACROSS THE SOUTH CENTRAL
PLAINS STATES DURING THE THURSDAY THROUGH SATURDAY TIME FRAME.
ALTHOUGH THERE DOES NOT APPEAR TO BE ANY STRONG SURFACE FEATURE
TO FIRE OFF ANY CONV ENOUGH MID LEVEL SUPPORT MAY OCCUR TO JUSTIFY
SOME BETTER POPS OUT AT DAY 7. SO ACCORDINGLY HAVE BUMPED POPS A
BIT HERE.

MODEL TO MODEL CONSENSUS AMONG THE GFS/ECMWF/CMC GUIDANCE HAS
GOTTEN BETTER IN THE HANDLING OF THE STRENGTH AND TIMING OF THE
FIRST MID LEVEL TROUGH AXIS THROUGH AROUND WED. THE MODEL
GUIDANCE BEGINS TO DIVERGE SOMEWHAT AFTER WED ESPECIALLY IN THE
TIMING OF THE VARIOUS SHORT WAVES DIGGING OVER THE DESERT
SOUTHWEST AND THE SOUTH CENTRAL PLAINS STATES. RUN TO RUN
CONSISTENCY WITH THE MEX MOS TEMP AND POPS GUIDANCE IS PRETTY
STABLE THROUGH DAY 7. SO OVERALL CONFIDENCE WITH THE UPCOMING
LONG RANGE FORECAST WORDING IS ABOVE AVERAGE.

MARINE...NOW THROUGH SUNDAY NIGHT...SEAS WERE AROUND 4 FEET AND
WINDS LESS THAN 10 KNOTS EARLY THIS AFTERNOON AT BUOY 42020.
LIGHT EAST WINDS WILL CONTINUE TODAY AND TONIGHT AS HIGH PRESSURE
WEAKENS AND CONTINUES TO THE EAST. WINDS WILL BECOME NORTHEASTERLY
SUNDAY AND SUNDAY NIGHT AS COASTAL TROUGHING STRENGTHENS ACROSS
THE COASTAL WATERS.

MONDAY THROUGH THURSDAY...FAIRLY CALM MARINE CONDITIONS WILL
PREVAIL FOR MON AND MON NIGHT AHEAD THE NEXT CANADIAN AIRMASS. THE
MARINE CONDITIONS WILL DEGRADE PRETTY QUICKLY ON TUES AND WILL
REMAIN PRETTY HAZARDOUS THROUGH WED AND WED NIGHT LIKELY REQUIRING
EITHER SCA OR GALE WATCHES/WARNINGS FOR THE BAY AND GULF WATERS.
THE PGF WILL START TO RELAX ON THURS ALLOWING THE MARINE
CONDITIONS TO IMPROVE ONCE AGAIN.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  66  79  68  79 /  10  10  20  20
BROWNSVILLE          64  81  65  81 /  10  10  20  20
HARLINGEN            62  81  63  82 /  10  10  20  20
MCALLEN              64  80  65  81 /  10  10  10  20
RIO GRANDE CITY      64  78  63  79 /  10  10  10  20
SOUTH PADRE ISLAND   68  79  69  78 /  10  10  20  20

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

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