Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 281858
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
200 PM EST SUN DEC 28 2014

.SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THE FLORIDA PENINSULA UNDER
THE PROTECTIVE COVER OF A LARGE MID/UPPER LEVEL RIDGE CENTERED NEAR
THE BAHAMAS. OUR DEEP LAYER FLOW ALOFT IS FROM THE SOUTH AND
SOUTHWEST BETWEEN THIS FEATURE AND A POTENT TROUGH/SHORTWAVE FEATURE
EJECTING QUICKLY EASTWARD ACROSS THE SOUTHERN PLAINS/NORTHERN
MEXICO. FINALLY FURTHER UPSTREAM WE SEE A SIGNIFICANT PIECE OF
ENERGY/JET STREAK DIVING DOWN OVER THE PACIFIC COAST. THROUGH THE
EARLY PORTION OF THE WEEK...OUT WEATHER WILL BE DETERMINED BY THE
INTERACTION BETWEEN THE RIDGE TO OUR SOUTH AND EAST...AND THE
APPROACHING SHORTWAVE FROM THE WEST.

AT THE SURFACE...ATLANTIC HIGH PRESSURE RIDGES BACK WEST INTO THE
FLORIDA PENINSULA AND EASTERN GULF...AND SHOULD HOLD IN PLACE
THROUGH MONDAY. TEMPERATURES HAVE WARMED INTO THE4 LOWER 80S INLAND
AND GENERALLY IN THE 70S AT THE COAST. ONLY EXCEPTION IS ALONG THE
IMMEDIATE COAST OVER THE FAR NORTHERN ZONES WHERE THE ONSHORE FLOW
IS OFF OF QUITE COOL SHELF WATERS. THE OBSERVATION AT CEDAR KEY IS
ONLY IN THE MIDDLE 60S. THESE TEMPS IN THE 60S ARE LIKELY CONFINED
TO ONLY A MILE OR TWO FROM THE WATER WITH TEMPERATURES RAPIDLY
WARMING WITH INLAND EXTENT.

&&

.SHORT TERM (REST OF TODAY THROUGH MONDAY)...
REST OF TODAY...
THE STRONG TERRESTRIAL HEATING AND GENERALLY WEAK GRADIENT HAVE
ALLOWED A FEEBLE SEA-BREEZE TO DEVELOP ALONG THE COAST THIS
AFTERNOON. THIS SEA-BREEZE WILL KEEP THE BEACHES A BIT COOLER
COMPARED WITH INLAND LOCATIONS AS THE FLOW IS OFF THE RELATIVELY
COOLER SHELF WATERS. THE FORECAST THE REST OF THE DAY IS FOR RAIN
FREE CONDITIONS DUE TO THE GENERALLY DRY COLUMN ALOFT AND NO
SYNOPTIC SUPPORT FOR LIFT IN THE VICINITY. THERE IS A COLD FRONT
STRETCHED ACROSS THE SOUTHEAST PORTION OF THE COUNTY THAT IS
BRINGING SHOWERS INTO THE FLORIDA PANHANDLE/AL/GA...HOWEVER THE
STRONG UPPER RIDGE WILL NOT ALLOW THIS FEATURE TO MOVE VERY FAR
THROUGH TONIGHT AND IT WILL NOT BE A CONCERN FOR OUR FORECAST TILL
AT LEAST TUESDAY.

TONIGHT...
FAIR AND DRY CONDITIONS CONTINUE. SHORTWAVE ENERGY WILL BE RAPIDLY
APPROACHING THE SOUTHEAST CONUS. HOWEVER...AS IT APPROACHES...THIS
ENERGY WILL BE QUICKLY SHEARING OUT AND DEAMPLIFYING. ABOUT THE ONLY
EFFECT THIS FEATURE WILL HAVE ON OUR LOCAL WEATHER THROUGH TONIGHT
WILL BE TO BREAK DOWN/DEAMPLIFY THE UPPER RIDGE AND BEGIN TO TURN
OUR SYNOPTIC FLOW ALOFT MORE ZONAL IN NATURE. THE SURFACE FRONT WILL
GET A LITTLE "KICK" EASTWARD WITH THE PASSING ENERGY...BUT SHOULD BE
STALLED NEAR APALACHEE BAY BY MONDAY MORNING. WE DO ANTICIPATE SOME
ADDITIONAL FOG/VISIBILITY ISSUES TONIGHT INTO EARLY MONDAY
MORNING...HOWEVER WITH THE RIDGE BREAKING DOWN OVERNIGHT...THE
SYNOPTIC SETUP FOR WIDESPREAD DENSE FOG DOES NOT LOOK AS FAVORABLE.
WILL GO WITH AREAS OF FOG...SOME OF WHICH SHOULD BECOME LOCALLY
DENSE. UNFORTUNATELY...MANY OF OUR AIRPORTS ARE IN LOWER/MORE FOG
PRONE LOCATIONS AND WILL PROB BE IMPACTED BY ANOTHER ROUND OF FLIGHT
RESTRICTIONS EARLY MONDAY.

MONDAY...
MORE OF THE SAME. AREAS OF FOG WILL SLOWLY BURN OFF BETWEEN 13-15Z.
THE UPPER RIDGE WILL BE DEAMPLIFIED...HOWEVER THE LOWER COLUMN WILL
STILL BE VERY WARM AND SUFFICIENT TO KEEP OUR TEMPS WELL ABOVE
AVERAGE. WOULD EXPECT LOWER 80S FOR HIGHS SOUTH OF THE I-4 CORRIDOR
AND AWAY FROM THE IMMEDIATE COAST. COULD CERTAINLY SEE LOWER 80S
FURTHER NORTH...HOWEVER ANTICIPATING A BIT MORE IN THE WAY OF CLOUDS
FOR CENTRAL AND NORTHERN PORTIONS OF THE STATE AND HENCE TEMPS MAY
BE HELD DOWN IN THE MID/UPPER 70S. THE FRONT LOOKS TO REMAIN
QUASI-STATIONARY UP ACROSS APALACHEE BAY SINCE THERE WILL STILL BE
LITTLE IN THE WAY OF ATMOSPHERIC PUSH. THE PROXIMITY OF THE FOCUS
ALONG THE BOUNDARY MAY BE ENOUGH TO SUPPORT A FEW SHOWERS UP TO LEVY
COUNTY...BUT OTHERWISE CONDITIONS ARE EXPECTED TO REMAIN DRY. THE
ONLY OTHER LOCATION THAT RUNS THE RISK OF A BRIEF AFTERNOON SHOWER
LOOKS TO BE AROUND HIGHLANDS COUNTY WHERE A FEW OF THE HIRES
EXPLICIT CONVECTION GUIDANCE MEMBERS ARE FOCUSING A FEW CONVECTIVE
CELLS AFTER 18Z ASSOCIATED WITH A SEA-BREEZE MERGER. GIVEN THE
COLUMN CHARACTERISTICS FOR TOMORROW...CAN NOT RULE OUT THE SUPPORT
FOR A BRIEF CONVECTIVE UPDRAFT AND WILL ADD A 20% POP FOR A SHOWER
OVER THE INLAND SOUTH-CENTRAL ZONES...EVEN THOUGH MOST SPOTS WILL
NOT SEE ANYTHING. EVEN UP TOWARD LEVY COUNTY WE DO NOT EXPECT ENOUGH
RAIN TO SERIOUSLY HAMPER ANY OUTDOOR EVENTS/ACTIVITIES. BEST RAIN
CHANCES ON MONDAY WILL STAY OFF TO THE NORTH AND NORTHWEST OF OUR
ZONES.

THE WEAK PASSING IMPULSE THAT FINALLY "SHOVES" THE FRONT DOWN INTO
THE FL PENINSULA IS ON TUESDAY...AND IT WILL BE AT THAT TIME THAT
LOW SHOWER CHANCES RETURN TO THE FORECAST FOR MOST OF US. HAVE A
GREAT SECOND HALF OF YOUR WEEKEND. GET OUTSIDE AND ENJOY THE WARM
LATE DECEMBER WEATHER!

&&

LONG TERM (TUESDAY THROUGH NEXT SUNDAY)...
THE PERIOD BEGINS ALOFT WITH A SHORT WAVE TROUGH ROUGHLY WEST TO
EAST ACROSS THE NORTHERN U.S. ROCKIES WHILE A ROBUST ATLANTIC
SUBTROPICAL RIDGE REACHED IN ACROSS THE SOUTHERN GULF OF MEXICO AND
THE NORTHWESTERN CARIBBEAN SEA. AT THE SURFACE HIGH PRESSURE
SPRAWLED ACROSS THE CANADIAN PRAIRIES AND THE NORTHERN AND CENTRAL
U.S. PLAINS WITH A LOW PRESSURE CENTER OFF THE MID-ATLANTIC COAST
THAT TRAILED A WEAK COLD FRONT BACK ACROSS SOUTH GA/NORTH FL INTO
THE GULF OF MEXICO.

WITH TIME THE SHORT WAVE TROUGH DROPS SOUTH ALONG THE SIERRA NEVADA
RANGE THEN DEEPENS INTO A CLOSED LOW AS IT TRACKS ACROSS THE GREAT
BASIN TO THE CENTRAL HIGH PLAINS. THE GULF AND CARIBBEAN RIDGE
BUILDS NORTHWARD OVER THE EASTERN STATES. MEANWHILE THE FRONT
SETTLES SOUTHWARD ACROSS THE REST OF FL AS IT SLOWLY DISSIPATES BY
WED AS THE SURFACE HIGH RELOCATES TO THE CENTRAL U.S. PLAINS AND
BUILDS OVER MUCH OF THE EASTERN CONUS.

DURING THE WEEKEND THE UPPER LOW OPENS INTO A TROUGH THAT TRACKS
NORTHEAST ACROSS THE GREAT LAKES INTO SOUTHEAST CANADA...ALONG WITH
A SURFACE REFLECTION TRAILING A COLD FRONT THAT GETS STRUNG OUT
ALONG THE EASTERN SEABOARD INTO THE CENTRAL GULF OF MEXICO. THE
RIDGING...BOTH ALOFT AND SURFACE...PIVOTS OUT OVER THE ATLANTIC AS
IT HANGS ON OVER MUCH OF BOTH FL AND THE GULF.

WHILE THE REST OF THE NATION WILL HAVE AN ACTIVE PATTERN THERE WILL
BE LIMITED IMPACT ACROSS WEST CENTRAL AND SOUTHWEST FL. THE FIRST
FRONT COMES THROUGH WITH ONLY SLIGHT CHANCE TO CHANCE SHOWERS MAINLY
TUE. THEN DRY CONDITIONS GENERALLY PREVAIL AS THE SECOND FRONT STAYS
TO THE NORTH THROUGH THE WEEKEND. HOWEVER...THE FRONT WILL BE CLOSE
ENOUGH FOR SOME ENERGY TO COMBINE WITH INCREASING MOISTURE ON
SOUTHERLY FLOW TO SUPPORT LOW CHANCE SHOWERS ACROSS THE NORTH SAT
AND SUN. TEMPERATURES INITIALLY ABOVE NORMAL COOL DOWN SLIGHTLY
MID-WEEK...AFTER THE FRONT MOVES THROUGH AND HIGH PRESSURE BUILDS IN
TO THE NORTHWEST AND NORTH. FOR THE END OF WEEK AND THE WEEKEND
TEMPERATURES REMAIN ABOVE NORMAL AND SLOWLY WARM AS THE HIGH MOVES
BY TO THE NORTH THEN NORTHEAST WITH LOW LEVEL EVENTUALLY VEERING TO
SOUTHERLY.

&&

AVIATION...
VFR CONDITIONS ARE GENERALLY PREVAILING ACROSS THE REGION THIS
AFTERNOON AND EXPECT THAT TREND TO CONTINUE THROUGH THE EVENING.
WINDS ARE LIGHT SOUTHERLY INLAND AND HAVE BECOME ONSHORE NEAR THE
COAST. WINDS WILL DISSIPATE AND BECOME LIGHT VARIABLE SHORTLY AFTER
SUNSET. AREAS OF FOG ARE EXPECTED TO ONCE AGAIN DEVELOP AFTER
MIDNIGHT AND LINGER THROUGH MID-MORNING MONDAY. ALTHOUGH NOT
EXPECTED TO BE AS WIDESPREAD AS SATURDAY NIGHT...THE POTENTIAL FOR
SEVERAL HOURS AT IFR OR LOWER DOES EXIST. MOST LIKELY SPOTS TO SEE
THE SIGNIFICANT RESTRICTIONS WILL BE KLAL...KPGD...KRSW AND KFMY.
ONCE THE FOG LIFTS BY 14-15Z MONDAY...VFR CONDITIONS ARE EXPECTED
FOR THE REMAINDER OF THE DAY.

&&

MARINE...
LIGHT SOUTH SOUTHEAST WINDS ON THE BACK SIDE OF HIGH PRESSURE OVER
THE WESTERN ATLANTIC WILL CONTINUE FOR THE NEXT COUPLE OF DAYS OVER
THE COASTAL WATERS. SEA FOG WILL BE POSSIBLE TODAY AND MONDAY WITH A
WARM AND HUMID AIR MASS OVERRIDING THE RELATIVELY COOLER WATERS. A
WEAK FRONTAL BOUNDARY APPROACHES THE AREA ON MONDAY AND TUESDAY
KEEPING THE SOUTHERLY WIND FLOW IN PLACE AND PRODUCING A SLIGHT
CHANCE OF SHOWERS. THE WINDS WILL SHIFT TO THE NORTH NORTHEAST IN
THE WAKE OF THIS FRONT ON TUESDAY...AND WILL REMAIN OUT OF THE
NORTHEAST THROUGH THE WEEK AS HIGH PRESSURE SETTLES INTO THE REGION.

&&

.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS FOR THE NEXT COUPLE OF DAYS
OTHER THAN AREAS OF DENSE FOG EXPECTED LATER TONIGHT INTO MONDAY
MORNING. RELATIVE HUMIDITY VALUES WILL REMAIN WELL ABOVE CRITICAL
LEVELS THROUGH TUESDAY WITH JUST A FEW SHOWERS AROUND ON TUESDAY.

FOG POTENTIAL...ALTHOUGH NOT EXPECTED TO BE AS WIDESPREAD AS
SATURDAY NIGHT...AREAS OF FOG ARE EXPECTED TO DEVELOP OVERNIGHT INTO
EARLY TUESDAY MORNING AND SOME OF THE FOG IS LIKELY TO BECOME DENSE.
DENSE FOG ADVISORIES MAY BECOME REQUIRED FOR SOME AREAS AFTER
MIDNIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  65  77  66  77 /   0  10  10  20
FMY  66  80  66  81 /   0  10  20  10
GIF  64  80  64  78 /   0  10  10  20
SRQ  64  77  65  76 /   0  10  10  10
BKV  60  79  63  77 /   0  10  20  20
SPG  66  76  66  76 /   0  10  20  10

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.

&&

$$

SYNOPSIS/SHORT TERM/AVIATION/FIRE WX...MROCZKA
MARINE...WYNN
LONG TERM...RUDE




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