418  
FXUS62 KMLB 220940  
AFDMLB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MELBOURNE FL  
440 AM EST MON JAN 22 2018  
   
DISCUSSION
 
 
CURRENT...GOES-16 SATELLITE IMAGERY INDICATES SHALLOW SEA FOG HAS  
DEVELOPED CLOSE TO THE VOLUSIA COUNTY COAST AS VEERING WINDS DRAW  
A MORE HUMID AIR MASS ATOP THE CHILLY SHELF WATERS. ALSO, WHERE  
WINDS HAVE DECOUPLED, SURFACE OBSERVATIONS INDICATE PATCHES OF  
GROUND FOG AND MIST WITH LOCAL VISIBILITY BELOW ONE- HALF OF A  
MILE. CURRENT CONFIGURATION OF PATCHY FOG LOOKS OK, AND WILL  
CONTINUE TO MONITOR UNTIL IT BEGINS BURNING OFF AFTER SUNRISE.  
 
TODAY...SURFACE HIGH PRESSURE SHIFTS SEAWARD AHEAD OF THE NEXT  
COLD FRONT MOVING THROUGH THE DEEP SOUTH. ALOFT, SHORTWAVE RIDGING  
WILL BUILD OVERHEAD, ALBEIT TEMPORARILY, AS THE BASE OF A  
LONGWAVE TROUGH SHIFTS OUT OF THE CENTRAL PLAINS.  
VEERING/INCREASING LOW LEVEL FLOW WILL DRAW A WARMER AND MORE  
HUMID AIR MASS ATOP THE PENINSULA AND CONTINUE THE STEADY WARMING  
TREND AS OF LATE. LIMITED MOISTURE (PWATS AT OR BELOW 1.00"  
THROUGH THE AFTERNOON) AND RIDGING ALOFT PRECLUDE THE NEED FOR  
POPS INTO THE AFTERNOON, THOUGH THAT WILL QUICKLY CHANGE AFTER  
SUNSET AS WE LOOK UPSTREAM TOWARD THE GULF. AFTERNOON HIGHS WILL  
BE SEVERAL DEGREES ABOVE NORMAL, WITH THE COOLER SHELF WATERS  
NORTH OF SEBASTIAN KEEPING TEMPS DOWN A BIT ALONG THE IMMEDIATE  
COAST OF BREVARD/VOLUSIA.  
 
TONIGHT...ENERGY ROUNDING THE BASE OF THE LARGE MID/UPPER TROUGH  
WILL SHIFT OVER THE GULF OF MEXICO. VEERING LOW-LEVEL FLOW OUT  
AHEAD OF THE ACCOMPANYING COLD FRONT WILL DRAW MOISTURE NORTHWARD  
AHEAD OF THE SYSTEM AND TRIGGER SCATTERED TO WIDESPREAD SHOWERS  
AND ISOLATED THUNDERSTORMS OVER THE EASTERN GULF OF MEXICO THIS  
EVENING. INCREASING SOUTHWESTERLY STEERING FLOW WILL CARRY SOME OF  
THIS ACTIVITY ACROSS THE PENINSULA, WITH THE GREATEST COVERAGE  
EXPECTED OVER THE NORTH PENINSULA WHERE MOST OF THE MID- LEVEL  
ENERGY IS EXPECTED TO PASS. LAKE AND VOLUSIA COUNTIES STAND TO SEE  
THE GREATEST CHANCES FOR SHOWERS OVERNIGHT (50-60%) ALONG WITH A  
SMALL THREAT OF THUNDER. FURTHER TO THE SOUTH, ONLY SHOWERS ARE  
EXPECTED, WITH POPS TAPERED TO AROUND 20% ALONG THE TREASURE  
COAST.  
 
TUE...A COLD FRONT WILL MAKE ITS SOUTHWARD ADVANCE THROUGH THE  
PENINSULA REACHING SOUTH FL BY WED EVEN TO THE FL STRAITS.  
CONSEQUENTLY, TUE WILL BE THE MAIN PERIOD FOR WIDER-SPREAD RAIN  
CHANCES ACROSS EAST CENTRAL FLORIDA. INCREASED MOISTURE AHEAD OF  
THE FRONT WILL BE SUFFICIENT FOR 40-50 PERCENT POPS WITH A LITTLE  
ASSISTANCE BY DAYTIME WARMING INTO THE M/U70S TO NEAR 80 DEGREES.  
HOWEVER, A CONSIDERABLE INCREASE IN CLOUDS WILL OTHERWISE OFFER  
CONSTRAINT. THE FRONT SHOULD BE LOCATED IN THE BIG BEND REGION  
AROUND SUNRISE WITH SHOWER ACTIVITY OUT AHEAD AFFECTING LOCATIONS  
MAINLY NORTH AND WEST OF INTERSTATE 4 WITH ISOLATED THUNDER STILL  
NOT OUT OF THE QUESTION. BY EARLY AFTERNOON (18Z), THE FRONT WILL  
HAVE GENERALLY REACHED A LINE FROM TAMPA TO THE CAPE, SLOWING TO  
ARRIVE IN VICINITY OF LAKE OKEECHOBEE BY EVENING (00Z). BY THIS  
TIME THE PARENT CYCLONE IS WELL REMOVED AND CRUISING ACROSS  
SOUTHEAST CANADA. WITH A FLATTENING MID/UPPER FLOW FOR THE SE  
CONUS, THE FRONT WILL LOSE ITS PUSH AND HANG-UP IN THE STRAITS.  
LOCAL DRAMA WILL BE REMOVED FOR ANY POST-FRONTAL WIND RUSH AND  
PRONOUNCED COLD ADVECTION. EVEN SO, LOW-LEVEL FLOW WILL TURN NW  
BEHIND THE BOUNDARY AND OFFER COOLING EFFECTS OVERNIGHT INTO WED  
AND WED NIGHT. MIN TEMPS IN THE M40S FOR THE NORTHERN INLAND  
REACHES OF LAKE/VOLUSIA COUNTIES, CONTRASTED BY U50S/L60S ON THE  
LOWER TREASURE COAST WHERE INFLUENCES OF THE RECENT FRONT WILL  
LINGER ALONG WITH SLIGHT POPS.  
 
WED-FRI...THE RECENT COLD FRONT WILL SETTLE IN VICINITY OF THE FL  
STRAITS ON WED AS HIGH PRESSURE BUILDS ACROSS THE SE CONUS. THE HIGH  
PRESSURE CENTER WILL TRANSITION EASTWARD TOWARD THE SEABOARD INTO  
LATE WEEK. LOCALLY, THIS WILL FACILITATE A PROGRESSIVE VEERING OF  
THE LOW-LEVEL WINDS FROM N ON WED TO E BY FRI. MORE SO, THE AREA  
PRESSURE GRADINET WILL TIGHTEN ACROSS CENTRAL FL BETWEEN THE TWO  
AFOREMENTIONED SYNOPTIC FEATURES, OFFERING A STIFF MARITIME  
ONSHORE FLOW THU/FRI. BEACH CONDITIONS WILL LIKELY DETERIORATE,  
ALONG WITH ISOLATED TO WIDELY SCATTERED COASTAL POPS RETURNING BY  
FRI NIGHT. THUS, THE MID-WEEK COOLING WILL BE SHORT-LIVED AND  
OVERTAKEN BY MARINE INFLUENCES BY LATE-WEEK. MAX TEMPS IN THE  
M/U60S-L70S. MIN TEMPS M40S NORTH/INTERIOR TO U50S-L60S  
SOUTH/COAST.  
 
SAT-SUN...MODELS SHOW RETURN FLOW GATHERING MOISTURE INTO THE BELLY  
OF THE NORTH-CENTRAL GULF OF MEXICO FUELING THE SOUTH END THE NEXT  
FRONTAL SYSTEM MOVING TOWARD THE E CONUS. THE FRONT IS POISED TO  
INFLUENCE LOCAL WEATHER BY SUN BRINGING INCREASED CHANCES FOR  
SHOWERS AND POSSIBLY STORMS. THE FRONT MAY ALSO BE AUGMENTED BY  
AREAS OF LOWERING PRESSURE AND TRANSIENT FRONTAL WAVES ALONG IT,  
ESPECIALLY OUT OVER THE EASTERN GULF AS IT APPROACHES THE PENINSULA.  
SOME UNCERTAINTY ABOUT TIMING AND EXTENT, BUT GROWING CONFIDENCE FOR  
AT LEAST INCLEMENT WX OCCURRENCE. SAT WILL LIKELY SERVE AS STAGING  
DAY FOR SUN. MAX TEMPS IN THE 70S, AND MIN TEMPS MAINLY IN 50S SAT  
MORNING AND 60S SUN MORNING.  
 

 
   
AVIATION
 
SURFACE OBSERVATIONS INDICATE SHALLOW GROUND FOG/MIST  
HAS DEVELOPED AT A FEW SITES EARLY THIS MORNING, EVIDENCED BY  
RAPID SWINGS IN VISIBILITY. EXPECT THIS TO CONTINUE THROUGH  
SUNRISE, THOUGH LONGER DURATIONS OF MVFR, EVEN IFR, ARE POSSIBLE  
AS PATCHY FOG DEVELOPS. THIS IS LESS LIKELY FROM KMLB SOUTH WHERE  
ONSHORE FLOW FROM THE ATLANTIC IS A BIT STRONGER. OTHERWISE, VFR  
EXPECTED INTO THIS EVENING BEFORE CLOUDS LOWER/THICKEN FROM NORTH  
TO SOUTH OVERNIGHT MONDAY AS SHOWERS MOVE ONSHORE FROM THE GULF OF  
MEXICO.  
 

 
   
MARINE
 
 
CURRENT...HIGH RESOLUTION SATELLITE IMAGERY, BEACH CAMS, AND  
OBSERVATIONS INDICATE SOME SEA FOG HAS DEVELOPED NEAR THE COAST OF  
VOLUSIA COUNTY. BOATERS ARE ADVISED THAT THE FOG IS LIKELY WITHIN  
THE INLETS AND OVER PARTS OF THE NEARSHORE WATERS.  
 
TODAY/TONIGHT...WINDS CONTINUE TO VEER AS HIGH PRESSURE SHIFTS  
SEAWARD AHEAD OF THE NEXT COLD FRONT. SOUTHEAST WINDS 10-15 KNOTS  
INCREASE OUT OF THE SOUTH TO AROUND 15 KNOTS OVERNIGHT. SEAS 2-3  
FEET NEARSHORE VOLUSIA/BREVARD, OTHERWISE 3-4 FEET. CHOPPY  
CONDITIONS EXPECTED SOUTH OF THE FT. PIERCE INLET AS THE BAHAMA  
SHADOW KEEPS DOMINANT WAVE PERIODS AT OR BELOW 5 SECONDS.  
 
TUE...INCREASING RAIN CHANCES AHEAD OF AN ADVANCING COLD FRONT  
FORECAST TO MOVE SOUTHWARD THROUGH THE WATERS DURING THE DAY.  
OFFSHORE MOVING SHOWERS WILL TRANSITION NORTH TO SOUTH FROM FLAGLER  
BEACH TO JUPITER INLET AS THE DAY PROGRESSES. ISOLATED THUNDER NOT  
OUT OF THE QUESTION FOR THE WATERS NORTH OF THE CAPE DURING THE  
MORNING. SW WINDS 5-10 KNOTS WITH SEAS 2-3 FEET NEARSHORE AND 10-15  
KNOTS WITH SEAS 3-4 FEET OFFSHORE AHEAD OF THE FRONT. WINDS SHIFTING  
TO NW/N BEHIND THE FRONT 10-15 KNOTS PROMPTING BUILDING SEAS TUE  
NIGHT, ESPECIALLY IN THE GULF STREAM 3-5 FEET.  
 
WED-FRI...THE PRESSURE GRADIENT WILL GRADUALLY TIGHTEN BEHIND THE  
COLD FRONT WHICH SETTLES INTO THE FLORIDA STRAITS ON WED. HIGH  
PRESSURE BUILDS ACROSS THE SE CONUS THEREBY PACKING THE LOCAL  
GRADIENT. WINDS WILL STEADILY VEER FROM N ON WED TO E BY FRI AS HIGH  
PRESSURE TRANSITIONS EASTWARD TOWARD THE SEABOARD. LOCAL SPEEDS  
INCREASE TO 15-20 KNOTS BY WED, TO AROUND 20 KNOTS THU, AND 20-25  
KNOTS THU NIGHT INTO FRI, ESPECIALLY OFFSHORE. CONDITIONS FOR SMALL  
CRAFT OPERATION WILL BECOME POOR BY WED NIGHT, THEN BECOME HAZARDOUS  
THU THROUGH FRI.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
DAB 73 64 75 50 / 10 60 50 10  
MCO 80 64 76 54 / 10 50 50 10  
MLB 77 65 78 58 / 10 30 40 20  
VRB 77 65 78 60 / 10 30 40 20  
LEE 79 64 74 50 / 10 60 40 10  
SFB 79 64 76 51 / 10 50 40 10  
ORL 80 64 76 53 / 10 50 50 10  
FPR 77 64 79 60 / 10 20 40 30  
 

 
   
MLB WATCHES/WARNINGS/ADVISORIES
 
 
FL...NONE.  
AM...NONE.  

 
 

 
 
SHORT TERM...WU  
LONG TERM....DS  
 
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