000 AXNT20 KNHC 171707 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST THU JAN 17 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1645 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH SOUTHERN COASTAL LIBERIA NEAR 5N9W TO 4N12W AND 5N17W. THE ITCZ CONTINUES FROM 5N17W TO 4N23W 2N30W 2N37W AND 1N43W. CONVECTIVE PRECIPITATION...SCATTERED STRONG FROM 3N TO 4N BETWEEN 29W AND 30W...AND FROM 4N TO 8N BETWEEN 33W AND 40W. ...DISCUSSION... THE GULF OF MEXICO... AN UPPER LEVEL TROUGH IS MOVING THROUGH MISSISSIPPI AND ALABAMA...REACHING THE GULF WATERS THAT ARE JUST OFF THE SOUTHEASTERN COAST OF LOUISIANA TO 28N93W. THE REST OF THE MIDDLE LEVEL TO UPPER LEVEL WIND FLOW THAT IS IN THE GULF OF MEXICO TO THE WEST OF 90W IS SOUTHWESTERLY. THE MIDDLE LEVEL WIND FLOW THAT IS TO THE EAST OF 90W IS PRINCIPALLY SOUTHWESTERLY WITH SOME SOUTHERLY WIND FLOW CLOSER TO THE FLORIDA STRAITS. THE TROUGH SUPPORTS A COLD FRONT THAT PASSES THROUGH FLORIDA ALONG 30N83W...TO 26N84W IN THE GULF OF MEXICO...INTO THE NORTHWESTERN CARIBBEAN SEA...ABOUT 30 NM OFF THE COAST OF THE YUCATAN PENINSULA...ACROSS NORTHERN BELIZE...AND NORTHERN GUATEMALA AND WESTERN GUATEMALA ALONG 16N AT ITS BORDER WITH MEXICO. BROKEN TO OVERCAST LOW CLOUDS... LIGHT RAIN...AND FOG...ARE BEING OBSERVED IN THE AREA FROM SARASOTA FLORIDA TO THE TAMPA/ST.PETERSBURG AREA. SIMILAR CONDITIONS ARE IN THE CLOUDINESS THAT ACCOMPANIES THE FRONT... WITHIN 150 TO 210 NM TO THE WEST OF THE LINE THAT PASSES THROUGH EXTREME NORTHEASTERN FLORIDA NEAR 31N81W 27N82W 24N84W...TO THE NORTHEASTERN CORNER OF THE YUCATAN PENINSULA...INTO SOUTHEASTERN GUATEMALA...AND IN THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO TO THE SOUTH OF 20N. BROKEN TO OVERCAST STRATIFORM CLOUDS ARE SWEEPING ACROSS THE GULF OF MEXICO BEHIND THE COLD FRONT. AREAS OF BROKEN LOW CLOUDS...LIGHT RAIN...AND FOG THAT COVERED SOUTHEASTERN COASTAL FLORIDA FROM MARATHON KEY TO FORT PIERCE DURING THE LATE NIGHT AND EARLY MORNING AND SUNRISE HOURS HAVE GIVEN WAY TO SCATTERED TO BROKEN LOW CLOUDS AND SOME MIDDLE LEVEL CEILINGS STUART FLORIDA SOUTHWARD. A SURFACE RIDGE EXTENDS FROM A 1035 MB HIGH PRESSURE CENTER THAT IS IN MEXICO NEAR 25N101W...TO 22N99W 20N97W...STRAIGHT TO THE ISTHMUS OF TEHUANTEPEC AND THE GULF OF TEHUANTEPEC. STORM-FORCE WINDS ARE BLOWING IN THE GULF OF TEHUANTEPEC OF MEXICO. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFEP2...AND THE EASTERN PACIFIC OCEAN TROPICAL WEATHER DISCUSSION...MIATWDEP... FOR MORE DETAILS. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE OFFSHORE FORECAST...MIAOFFNT4...FOR DETAILS ABOUT THE GALE WARNING WITH THE 30N83W 21N87W COLD FRONT...TO THE SOUTH OF 20N TO THE EAST OF 94W...WITH 10 TO 14 FOOT SEA HEIGHTS. A SECOND GALE WARNING COVERS THE AREA THAT IS TO THE NORTH OF 28N TO THE EAST OF 87W...WITH 8 TO 11 FOOT SEA HEIGHTS. EXPECT 20 TO 25 KNOT WINDS AND 8 TO 10 FOOT SEA HEIGHTS TO THE WEST OF THE FRONT TO 30N93W 22N98W. THE CARIBBEAN SEA... UPPER LEVEL SOUTHWESTERLY WIND FLOW STREAMS ACROSS CENTRAL AMERICA FROM NICARAGUA TO EASTERN PANAMA TOWARD HISPANIOLA... AND THEN IT CONTINUES NORTHWARD AS IT IS CAUGHT UP IN THE LARGE- SCALE ANTICYCLONIC WIND FLOW THAT IS IN THE ATLANTIC OCEAN... THAT IS MOVING AROUND THE 28N64W ANTICYCLONIC CENTER. A MIDDLE LEVEL TO UPPER LEVEL RIDGE IS ALONG 67W FROM 8N IN VENEZUELA BEYOND PUERTO RICO. SOME OF THE MIDDLE LEVEL WIND FLOW THAT IS IN THE AREA OF 15N/16N ALONG 67W ALSO IS CAUGHT UP IN THE ANTICYCLONIC WIND FLOW THAT IS RELATED TO THE 28N64W ANTICYCLONIC CENTER. OTHER MIDDLE LEVEL WIND FLOW IS NORTHEASTERLY AS IT MOVES TOWARD NORTHWESTERN VENEZUELA AND COLOMBIA. MIDDLE LEVEL TO UPPER LEVEL SOUTHERLY WIND FLOW COVERS THE REST OF THE NORTHWESTERN PART OF THE AREA...AWAY FROM THE SOUTHWESTERLY WIND FLOW THAT IS CROSSING CENTRAL AMERICA. THIS WIND FLOW ALSO EVENTUALLY IS CAUGHT UP IN THE BROAD ATLANTIC OCEAN ANTICYCLONIC WIND FLOW...AND THE SOUTHERLY WIND FLOW THAT IS IN THE EASTERN GULF OF MEXICO WITH THE ADVANCING TROUGH AND GULF OF MEXICO COLD FRONT. COMPARATIVELY DRIER AIR IN SUBSIDENCE COVERS THE ENTIRE CARIBBEAN SEA...IN WATER VAPOR IMAGERY. RAINSHOWERS ARE POSSIBLE IN CLUSTERS OF BROKEN LOW LEVEL TO MIDDLE LEVEL CLOUDS...TO THE EAST OF 70W...TO THE NORTH OF 12N BETWEEN 70W AND 77W AND TO THE NORTH AND NORTHWEST OF 12N77W 11N80W 9N81W...AND ELSEWHERE TO THE WEST OF 80W. THE MONSOON TROUGH IS ALONG 8N74W IN COLOMBIA...THROUGH EASTERN PANAMA ALONG 78W...9N80W...THROUGH WESTERN PANAMA AND BEYOND 9N84W IN SOUTHERN COSTA RICA...INTO THE EASTERN PACIFIC OCEAN BEYOND 7N90W. CONVECTIVE PRECIPITATION...WIDELY SCATTERED TO SCATTERED MODERATE TO THE NORTH OF 6N BETWEEN 83W AND 90W... SOME OF IT REACHING THE COASTAL AREAS OF WESTERN PANAMA AND COSTA RICA. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT THE 20 TO 25 KNOT WINDS AND 9 FOOT SEA HEIGHTS FROM 11N TO 17N BETWEEN 70W AND 78W. EXPECT A COLD FRONT TO REACH 23N83W 17N88W IN ABOUT 12 HOURS. 20 TO 25 KNOT WINDS WILL BE TO THE WEST OF THE COLD FRONT...AND SEA HEIGHTS WILL REACH 10 FEET IN THE YUCATAN CHANNEL. THE ATLANTIC OCEAN... GALE FORCE WIND IS DEVELOPING DURING THE NEXT 12 HOURS IN THE ATLANTIC OCEAN OFF THE COAST OF NORTHEASTERN FLORIDA. THIS WIND IS IN ADVANCE OF THE COLD FRONT THAT CURRENTLY PASSES THROUGH FLORIDA ALONG 30N83W...TO 26N84W IN THE GULF OF MEXICO...INTO THE NORTHWESTERN CARIBBEAN SEA...ABOUT 30 NM OFF THE COAST OF THE YUCATAN PENINSULA...ACROSS NORTHERN BELIZE...AND NORTHERN GUATEMALA AND WESTERN GUATEMALA ALONG 16N AT ITS BORDER WITH MEXICO. A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS ALONG 30N36W TO 25N38W TO A 23N40W CYCLONIC CIRCULATION CENTER...TO 15N40W 9N45W 6N53W. THE TROUGH SUPPORTS A 1013 MB LOW PRESSURE CENTER THAT IS NEAR 23N40W. A SURFACE TROUGH EXTENDS FROM THE LOW CENTER TO 22N38W 18N40W 13N45W. CONVECTIVE PRECIPITATION...SCATTERED STRONG FROM 21N TO 24N BETWEEN 34W AND 37W...SCATTERED MODERATE FROM 21N TO 23N BETWEEN 32W AND 35W...ISOLATED MODERATE ELSEWHERE FROM 17N TO 28N BETWEEN 28W AND 42W. A MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC CIRCULATION CENTER IS NEAR 28N64W. ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN TO THE NORTH OF 18N BETWEEN 54W AND 80W. AN EASTERN ATLANTIC OCEAN UPPER LEVEL RIDGE IS ALONG 5N18W 18N18W BEYOND 32N25W. A WESTERN ATLANTIC OCEAN SURFACE RIDGE IS ALONG 19N57W 21N68W 30N76W...BEYOND A 1024 MB HIGH PRESSURE CENTER THAT IS NEAR 33N72W. AN EASTERN ATLANTIC OCEAN SURFACE RIDGE EXTENDS FROM A 1028 MB HIGH PRESSURE CENTER THAT IS NEAR 33N17W IN THE MADEIRA ARCHIPELAGO...TO THE WESTERN CAPE VERDE ISLANDS. ANOTHER SURFACE RIDGE EXTENDS FROM THE 33N17W HIGH PRESSURE CENTER WESTWARD TO 33N30W 34N47W...TO A 1026 MB HIGH PRESSURE CENTER THAT IS NEAR 32N58W...TO 32N65W NEAR BERMUDA...TO 27N74W TO THE FLORIDA STRAITS. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE DETAILS ABOUT...THE GALE WARNING...GALE-FORCE WINDS AND SEA HEIGHTS RANGING FROM 8 TO 10 FEET...AT 12 HOURS INTO THE FORECAST PERIOD...WITH THE COLD FRONT AT THAT TIME FROM 31N78W TO 28N80W...25 TO 35 KNOT WINDS AND 8 TO 10 FOOT SEA HEIGHTS TO THE NORTH OF 29N TO THE WEST OF 78W. A 1013 MB LOW PRESSURE CENTER IS NEAR 23N40W. A SURFACE TROUGH EXTENDS FROM THE LOW CENTER TO 22N38W AND 13N45W. EXPECT 20 TO 30 KNOT WINDS AND 8 TO 12 FOOT SEA HEIGHTS WITHIN 210 NM TO THE NORTH AND EAST OF THE LOW CENTER AND TROUGH. EXPECT 20 KNOT WINDS OR LESS AND 8 TO 10 FOOT SEA HEIGHTS ELSEWHERE TO THE NORTH OF 18N TO THE EAST OF THE LINE 18N59W 31N50W. EXPECT ADDITIONALLY...AT 12 HOURS INTO THE FORECAST PERIOD...20 TO 30 KNOT WINDS AND SEA HEIGHTS LOWER THAN 8 FEET WITHIN 150 NM TO THE EAST OF THE FRONT...AND 20 TO 25 KNOT WINDS AND SEA HEIGHTS LOWER THAN 8 FEET TO THE WEST OF THE FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT