000
FXUS62 KKEY 230243
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
1040 PM EDT WED MAY 22 2013
.DISCUSSION...
CONSIDERABLE DRY AIR ALOFT KEPT THE CLOUD LINE FLAT FOR MOST OF
THE ISLAND CHAIN...EXCEPT FROM 5 TO 10 NM NORTH OF THE ISLAND CHAIN
BETWEEN THE SEVEN MILE BRIDGE AND LONG KEY. THIS NARROW BAND FORMED
IN THIS AREA BEFORE DISINTEGRATING FOR A BRIEF SPELL. HOWEVER...IT
REGENERATED SHORTLY BEFORE 3 PM WITH A SOLID...ALBEIT FAIRLY SHORT
SEGMENT OF SHOWERS...THUNDERSTORMS ALONG WITH SEVERAL WATERSPOUTS
FROM BAHA HONDA TO NEAR MARATHON INCLUDING THE SEVEN MILE BRIDGE.
THIS CYCLICAL...EXTREMELY DEEP AND ACTIVE CLOUD LINE PERSISTED FROM
AROUND 245 PM TO 520 PM. ELSEWHERE...NO PRECIPITATION IMPACTED THE
FLORIDA KEYS UNTIL LATE THIS EVENING WHEN A PERSISTENT BAND OF
SHOWERS AND THUNDERSTORMS SLIPPED SOUTHWARD INTO THE EXTREME UPPER
KEYS...BETWEEN NORTH KEY LARGO AND ANGELFISH KEY. CURRENTLY...IN
ADDITION TO THE DEEP CONVECTION IN THE EASTERNMOST UPPER KEYS AND
THE ADJACENT NEARSHORE ATLANTIC WATERS...SHOWERS ARE DECAYING ON THE
OFFSHORE WATERS BEYOND 20 NM SOUTH OF THE LOWER KEYS. IN
ADDITION...SEVERAL BOUNDARIES ARE LINGERING JUST NORTH AND SOUTH OF
THE ISLAND CHAIN. ACROSS OUR MARINE DISTRICT...WINDS ARE VARIABLE AT
LESS THAN 10 KNOTS AWAY FROM ANY SHOWERS AND THUNDERSTORMS.
OTHERWISE...OUR EVENING SOUNDING REVEALS LIMITED MOISTURE (PWAT 1.30
INCHES) BUT WITH LITTLE IF ANY CONVECTIVE INHIBITION. LIGHT AND
VARIABLE WINDS TURN QUICKLY WEST TO NORTHWEST AND INTENSIFY ABOVE
400 MB.
.SHORT TERM (REST OF TONIGHT)...
DESPITE CONSIDERABLE MID AND UPPER LEVEL DRY AIR ABOVE 700 MB...A
PLETHORA OF BOUNDARIES COMBINED WITH LITTLE IN THE WAY OF CONVECTIVE
INHIBITION WILL POSE A 20 TO 30 PERCENT CHANCE FOR SHOWERS AND
POSSIBLE THUNDERSTORMS ACROSS THE ISLAND CHAIN. LIGHT AND VARIABLE
WINDS UNDER MAINLY PARTLY CLOUDY SKIES WILL ALLOW TEMPERATURES TO
FALL BETWEEN 75 AND 80 DEGREES ALONG THE FLORIDA KEYS. SINCE THE
CURRENT FORECAST HANDLES THE FORECAST ELEMENTS FAIRLY WELL...NO
ADJUSTMENTS ARE PLANNED.
&&
.MARINE...
OUR EVENING SOUNDING INDICATES NORTHWEST AND WEST WINDS OF 6 AND 2
KNOTS RESPECTIVELY WHILE THE KBYX VWP DEPICTS NORTHWEST AT 10 KNOTS
AT 1 THOUSAND FEET. WITH OUR REGION LYING BETWEEN A WESTERN ATLANTIC
RIDGE LYING JUST EAST OF THE FLORIDA PENINSULA AND ANOTHER AREA OF
HIGH PRESSURE IN THE EASTERN GULF OF MEXICO...WINDS WILL BE VARIABLE
AT LESS THAN 10 KNOTS ON ALL KEYS COASTAL WATERS OUTSIDE OF SHOWERS
AND THUNDERSTORMS.
&&
.AVIATION...
THROUGH 24/00Z...VFR CONDITIONS SHOULD PREVAIL AT THE KEY WEST AND
MARATHON TERMINALS. IN THE SHORT TERM...THE ONLY EXCEPTION TO THAT
SHOULD BE THE POSSIBILITY OF LIGHT SHOWERS OR BRIEF MVFR CIGS FROM A
PASSING BOUNDARY SOMETIME AFTER 04Z. WITH AMPLE REMNANT BOUNDARIES
IN THE VICINITY OF THE ISLAND CHAIN...THERE WILL BE A CONTINUAL
SLIGHT CHANCE OF SHOWERS IN THE AREA THROUGH THURSDAY...BUT
CONFIDENCE IS LACKING IN THE EXACT TIME PERIOD OF THOSE SHOWERS.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE/FIRE/DIGITAL...APA
AVIATION/NOWCASTS............MSB
DATA ACQUISITION.............BWC
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 221834
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
235 PM EDT WED MAY 22 2013
.DISCUSSION...
.CURRENTLY...
KBYX DETECTS ISOLATED SHOWERS OVER FLORIDA BAY AND NEARSHORE GULF OF
MEXICO WATERS NORTH OF THE MIDDLE KEYS. ELSEWHERE...KBYX DETECTS NO
PRECIPITATION ECHOES IN THE REMAINDER OF THE FORECAST AREA. SKIES
OVER THE ISLAND CHAIN ARE PARTLY CLOUDY. WINDS OVER LAND ARE SOUTH
TO SOUTHWEST AT 5 TO 10 MPH. C-MAN WINDS...ON AVERAGE...ARE
SOUTHWEST AT 5 TO 10 KNOTS. TEMPERATURES RANGE FROM THE MID 80S TO
THE LOWER 90S.
.SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...
AN ATLANTIC RIDGE OF HIGH PRESSURE ACROSS NORTH FLORIDA WILL RETREAT
EASTWARD TONIGHT. A WEAK PRESSURE PATTERN WILL PREVAIL THURSDAY
THROUGH FRIDAY. A LARGE AREA OF HIGH PRESSURE OVER THE OHIO VALLEY
WILL BEGIN TO BUILD SOUTHWARD DOWN THE FLORIDA PENINSULA FRIDAY
NIGHT. PRECIPITABLE WATER VALUES SHOULD BE NEAR ONE AND ONE QUARTER
OF AN INCH TONIGHT THROUGH FRIDAY NIGHT. THE ANTICIPATED PRESENCE OF
THIS RELATIVELY DRY AIR MASS WILL LIMIT POPS TO SLIGHT CHANCE
CATEGORY TONIGHT THROUGH FRIDAY NIGHT.
.LONG TERM (SATURDAY THROUGH WEDNESDAY)...
THE AFOREMENTIONED AREA OF HIGH PRESSURE WILL CONTINUE TO BUILD
SOUTHWARD DOWN THE FLORIDA PENINSULA SATURDAY THROUGH SUNDAY NIGHT.
AN ATLANTIC RIDGE OF HIGH PRESSURE WILL EXTEND ACROSS THE
SOUTHEASTERN UNITED STATES MONDAY THROUGH WEDNESDAY. LACK OF
ATMOSPHERIC MOISTURE WILL LIMIT POPS TO SLIGHT CHANCE CATEGORY
SATURDAY THROUGH SUNDAY. ATMOSPHERIC MOISTURE SHOULD INCREASE ENOUGH
TO SUPPORT LOW CHANCE POPS SUNDAY NIGHT THROUGH WEDNESDAY.
&&
.MARINE...
LIGHT SOUTHWEST BREEZES WILL PREVAIL ON ALL KEYS COASTAL WATERS
TONIGHT. NO ADVISORIES OR CAUTIONARY HEADLINES EXPECTED TONIGHT
THROUGH AT LEAST SATURDAY MORNING. SMALL CRAFT ARE URGED TO EXERCISE
CAUTION ON ALL KEYS COASTAL WATERS SATURDAY AFTERNOON DUE TO
SUSTAINED NORTHEAST SURFACE WINDS OF 15 TO 20 KNOTS. A SMALL CRAFT
ADVISORY WILL LIKELY BE REQUIRED FOR ALL KEYS COASTAL WATERS
SATURDAY NIGHT THROUGH MONDAY NIGHT.
&&
.AVIATION...
THROUGH THIS EVENING...VFR CONDITIONS WILL PREVAIL AT THE KEY WEST
AND MARATHON TERMINALS. WINDS WILL BE MAINLY LIGHT AND VARIABLE AT
BOTH TERMINALS.
&&
.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1985...THE LOW TEMPERATURE
AT KEY WEST INTERNATIONAL AIRPORT WAS 82 DEGREES. THIS SET THE DAILY
RECORD FOR WARMEST MINIMUM TEMPERATURE MEASURED IN KEY WEST ON MAY
22ND...A RECORD WHICH STILL STANDS 28 YEARS LATER. IN ADDITION...
THIS LOW TEMPERATURE OF 82 DEGREES IS THE WARMEST MINIMUM
TEMPERATURE EVER RECORDED IN KEY WEST DURING THE MONTH OF MAY.
TEMPERATURE RECORDS AT KEY WEST DATE BACK TO 1872.
&&
.PRELIMINARY POINT TEMPS/POPS...
KEY WEST 80 87 77 87 / 10 20 10 10
MARATHON 81 89 77 89 / 10 20 10 10
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE/CLIMATE/FIRE/DIGITAL...BS
AVIATION/NOWCASTS....................DEVANAS
DATA ACQUISITION.....................BWC
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 221508
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
1110 AM EDT WED MAY 22 2013
.DISCUSSION...
.CURRENTLY...
KBYX DETECTS ISOLATED SHOWERS OVER THE UPPER KEYS...AS WELL AS OVER
NEARSHORE WATERS SURROUNDING THE UPPER KEYS. ELSEWHERE...KBYX
DETECTS NO PRECIPITATION ECHOES IN THE REMAINDER OF THE FORECAST
AREA. SKIES OVER THE ISLAND CHAIN ARE PARTLY CLOUDY. WINDS OVER LAND
ARE SOUTH TO SOUTHWEST AT 5 TO 10 MPH. C-MAN WINDS...ON AVERAGE...
ARE SOUTH TO SOUTHWEST NEAR 10 KNOTS. TEMPERATURES ARE IN THE MID TO
UPPER 80S.
.SHORT TERM (THIS AFTERNOON)...
IN THE LOW LEVELS OF THE ATMOSPHERE...AN ATLANTIC RIDGE OF HIGH
PRESSURE ACROSS NORTH FLORIDA WILL RETREAT EASTWARD THIS AFTERNOON.
IN THE MID TO UPPER LEVELS OF THE ATMOSPHERE...A TROUGH OF LOW
PRESSURE WILL BE CENTERED JUST OFFSHORE OF THE EAST COAST OF THE
FLORIDA PENINSULA TODAY. THE 12Z KKEY SOUNDING IS VERY UNSTABLE AND
SEASONABLY MOIST FOR THIS TIME OF YEAR...WITH A PRECIPITABLE WATER
(PWAT) VALUE JUST UNDER ONE AND ONE HALF OF AN INCH. ATMOSPHERIC
MOISTURE WILL DECREASE A BIT THIS AFTERNOON. BY SUNSET THIS
EVENING...PWAT VALUES WILL BE JUST ABOVE ONE AND ONE QUARTER OF AN
INCH. RAIN CHANCES WILL BE KEPT NEAR THE UPPER END OF ALL NUMERICAL
MODEL OUTPUT STATISTICS FOR THIS AFTERNOON DUE TO THE POTENTIAL FOR
ISLAND CUMULUS CLOUD LINES DEVELOPING NEAR OR DIRECTLY OVER THE
FLORIDA KEYS.
&&
.MARINE...
GENTLE SOUTH TO SOUTHWEST BREEZES WILL BECOME LIGHT AND VARIABLE ON
ALL KEYS COASTAL WATERS THIS AFTERNOON. NO ADVISORIES OR CAUTIONARY
HEADLINES EXPECTED THIS AFTERNOON THROUGH AT LEAST SATURDAY MORNING.
SMALL CRAFT ARE URGED TO EXERCISE CAUTION ON ALL KEYS COASTAL WATERS
SATURDAY AFTERNOON DUE TO SUSTAINED NORTHEAST SURFACE WINDS OF 15 TO
20 KNOTS. A SMALL CRAFT ADVISORY WILL LIKELY BE REQUIRED FOR ALL
KEYS COASTAL WATERS SATURDAY NIGHT THROUGH SUNDAY NIGHT.
&&
.AVIATION...
THROUGH THIS AFTERNOON...VFR CONDITIONS WILL PREVAIL AT THE KEY WEST
AND MARATHON TERMINALS. LIGHT AND VARIABLE SURFACE WINDS WILL ALLOW
FOR A CLOUD LINE EXTENDING EASTWARD ALONG THE ISLAND CHAIN.
HOWEVER...SHOWERS WILL BE LIMITED DUE TO DRIER AIR ALOFT. THEREFORE
BRIEF MVFR CEILINGS ARE POSSIBLE...BUT NOT LIKELY.
&&
.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1985...THE LOW TEMPERATURE
AT KEY WEST INTERNATIONAL AIRPORT WAS 82 DEGREES. THIS SET THE DAILY
RECORD FOR WARMEST MINIMUM TEMPERATURE MEASURED IN KEY WEST ON MAY
22ND...A RECORD WHICH STILL STANDS 28 YEARS LATER. IN ADDITION...
THIS LOW TEMPERATURE OF 82 DEGREES IS THE WARMEST MINIMUM
TEMPERATURE EVER RECORDED IN KEY WEST DURING THE MONTH OF MAY.
TEMPERATURE RECORDS AT KEY WEST DATE BACK TO 1872.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE/CLIMATE/FIRE/DIGITAL...BS
AVIATION.............................DEVANAS
DATA ACQUISITION.....................VICKERY
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 221140 AAA
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS...UPDATED
NATIONAL WEATHER SERVICE KEY WEST FL
740 AM EDT WED MAY 22 2013
.AVIATION...
THROUGH THE 23RD/12Z...VFR WILL PREVAIL AT THE EYW AND MTH
TERMINALS. BY THE AFTERNOON...LIGHT AND VARIABLE SURFACE
WINDS...COMBINED WITH WESTERLY LOW TO MID-LEVEL FLOW...WILL ALLOW FOR
A CLOUD LINE ALONG THE ISLAND CHAIN. CURRENT FORECAST SOUNDINGS
INDICATE DRY AIR INTRUSION WILL LIMIT THE ROBUSTNESS AND
PRECIPITATING ABILITY OF THE CLOUD LINE.
&&
$$
AVIATION...CLR
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 220825
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
425 AM EDT WED MAY 22 2013
.DISCUSSION...
.CURRENTLY...
RADAR DETECTS WIDELY SCATTERED SHOWERS OVER MIAMI-DADE COUNTY...
THE EASTERN FLORIDA STRAITS SOUTHEAST OF THE UPPER KEYS...AND OVER
THE OFFSHORE GULF WATERS. MORE SHOWERS WERE PRESENT EARLIER IN THE
NIGHT ACROSS THE UPPER KEYS AND ADJACENT NEARSHORE WATERS...BUT
ACTIVITY THERE HAS DIMINISHED CONSIDERABLY DURING THE PAST COUPLE OF
HOURS. SKIES ARE PARTLY CLOUDY ACROSS THE KEYS...WITH TEMPERATURES
ALONG THE ISLAND CHAIN HOVERING IN THE UPPER 70S TO NEAR 80 DEGREES...
AND WINDS ON LAND FROM THE SOUTHEAST TO SOUTH AT 5 TO 10 KNOTS.
SURFACE ANALYSIS DEPICTS HIGH PRESSURE OVER THE WESTERN ATLANTIC...
WITH A WEAKENING RIDGE AXIS EXTENDING ACROSS NORTH FLORIDA AND INTO
THE EASTERN GULF OF MEXICO. ALOFT...A SMALL MID/UPPER LEVEL TROUGH IS
SLOWLY MOVING EASTWARD FROM THE FLORIDA PENINSULA...ALLOWING DRY
NORTHWEST FLOW TO SPREAD ACROSS THE KEYS IN ITS WAKE. THE TUESDAY
EVENING KEY WEST SOUNDING REMAINED UNSTABLE AND RELATIVELY MOIST
IN THE LOWER LEVELS...BUT SIGNIFICANT DRY AIR IS PRESENT ABOVE 700
MB THANKS TO THE AFOREMENTIONED DEEP NORTHWEST FLOW.
.SHORT TERM (TODAY THROUGH FRIDAY)...
THE MID/UPPER LEVEL TROUGH THAT HAS LINGERED OVER FLORIDA FOR THE
PAST FEW DAYS WILL MOVE NORTHEAST AND BECOME ENTRAINED INTO A MUCH
LARGER MID LATITUDE TROUGH ADVANCING INTO THE EASTERN CONUS DURING
THE NEXT COUPLE OF DAYS. THIS TROUGH WILL THEN SHARPEN ALONG THE
EASTERN SEABOARD THURSDAY NIGHT AND FRIDAY. THIS SYNOPTIC PATTERN
WILL PROMOTE DEEP AND DRY NORTHWEST FLOW ALOFT ACROSS THE KEYS...
WHICH WILL KEEP RAIN CHANCES LOW THROUGH MOST OF THE PERIOD.
FOR TODAY...WE WILL HAVE ONE MORE CHANCE FOR AT LEAST A MODEST CLOUD
LINE DEVELOPMENT...AS MODEL SOUNDINGS INDICATE SUFFICIENT LOW LEVEL
MOISTURE AND INSTABILITY REMAINING IN PLACE ALONG WITH A DECENT WIND
PROFILE FOR A REVERSE CU LINE. DRY AIR ALOFT WILL LIKELY LIMIT THE
VERTICAL GROWTH OF ANY LINE THAT DOES DEVELOP...AND FEEL THAT THE
EXISTING LOW CHANCE POPS WITH JUST A SLIGHT CHANCE OF THUNDER WILL
SUFFICE.
TONIGHT THROUGH THURSDAY NIGHT...A RATHER DRY AIRMASS FOR LATE MAY
(PWATS ONLY 60-80 PERCENT OF NORMAL) WITH LARGE DEWPOINT DEPRESSIONS
THROUGHOUT THE MID LEVELS AND EVEN EXTENDING DOWN INTO THE LOWER
LEVELS SHOULD SERIOUSLY LIMIT CONVECTIVE DEVELOPMENT. WOULD EXPECT
NOTHING MORE THAN ISOLATED TO WIDELY SCATTERED SHOWERS ALONG VARIOUS
SLOW MOVING BOUNDARIES WITHIN A VERY WEAK SYNOPTIC FLOW REGIME. WILL
MAINTAIN THE EXISTING 20 PERCENT POPS...AND THESE MAY WELL BE TOO
GENEROUS.
ON FRIDAY...DEVELOPING NORTHERLY STEERING FLOW COULD ALLOW FOR ANY
MAINLAND CONVECTION THAT MAY BE PRESENT TO DRIFT INTO THE KEYS DURING
THE LATER AFTERNOON AND EVENING HOURS. A BIT MORE MID LEVEL MOISTURE
MAY BE AVAILABLE BY THEN AS WELL. STILL EXPECT COVERAGE TO BE SPARSE...
AND WILL MAINTAIN 20 PERCENT POPS WITH A THUNDER MENTION.
TEMPERATURES WILL CHANGE LITTLE...WITH HIGHS MOSTLY IN THE UPPER 80S
(NEAR 90 AT THE WARMEST SPOTS SUCH AS MARATHON AIRPORT). WILL OPEN UP
A SMALL RANGE OF MID-UPPER 70S FOR LOWS...AS MOSTLY CLEAR SKIES AND
NEAR CALM CONDITIONS SHOULD ALLOW FOR NIGHTTIME LOWS TO DIP SLIGHTLY
AT SHELTERED INTERIOR ISLAND LOCATIONS.
&&
.LONG TERM (FRIDAY NIGHT THROUGH TUESDAY)...
THE DEEP MID LATITUDE TROUGH FORECAST TO BE JUST OFF THE EASTERN
SEABOARD AS THE LONG TERM PERIOD BEGINS SHOULD CONTINUE MOVING
EASTWARD...WITH SURFACE HIGH PRESSURE BUILDING ACROSS THE EASTERN
CONUS IN ITS WAKE. THIS PATTERN CHANGE WILL PROMOTE INCREASING
EASTERLY FLOW ACROSS THE KEYS STARTING LATE SATURDAY...WITH BREEZY
CONDITIONS EXPECTED SATURDAY NIGHT THROUGH TUESDAY. A RATHER DRY
AIRMASS FOR THIS TIME OF YEAR WILL REMAIN IN PLACE ACROSS OUR AREA
THROUGH SUNDAY. WILL KEEP THE EXISTING 20 PERCENT POPS FOR NOW...
ALTHOUGH THE LATEST ECMWF MOS GUIDANCE IN PARTICULAR SUGGESTS THAT
THOSE MAY BE TOO HIGH. LOW LEVEL MOISTURE SHOULD GRADUALLY INCREASE
WITHIN THE BRISK EASTERLY FLOW EARLY NEXT WEEK...AND WILL CONTINUE
WITH THE EXISTING LOW CHANCE POPS...WHICH ARE SLIGHTLY ABOVE CLIMO
FOR THE END OF MAY. NO CHANGE TO TEMPS.
&&
.MARINE...
AN ASCAT PASS FROM LATE TUESDAY EVENING SHOWED GENTLE TO MODERATE
SOUTHEAST FLOW ACROSS THE KEYS WATERS...AND WINDS HAVE CONTINUED TO
SLOWLY TREND DOWNWARD AT MOST OF THE REPORTING STATIONS SINCE THEN.
GENTLE SOUTHEAST FLOW THIS MORNING WILL BECOME VARIABLE BY MIDDAY
AS THE PRESSURE PATTERN ACROSS THE REGION COLLAPSES. EXPECT LIGHT
AND VARIABLE WINDS TO PREVAIL FROM THIS AFTERNOON THROUGH THURSDAY
NIGHT...WITH DIURNAL SEABREEZE CIRCULATIONS OVER THE MAINLAND
DOMINATING THE FLOW PATTERN. GENTLE NORTHERLY FLOW WILL DEVELOP
ACROSS THE KEYS WATERS FRIDAY AND FRIDAY NIGHT...THEN VEER TO THE
NORTHEAST AND INCREASE SIGNIFICANTLY ON SATURDAY. EXERCISE CAUTION
HEADLINES MAY BE NEEDED BY SOMETIME SATURDAY AFTERNOON...AND THERE
IS A GOOD CHANCE THAT SMALL CRAFT ADVISORIES WILL BE NEEDED FOR MOST
OR ALL OF THE KEYS WATERS FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT.
&&
.AVIATION...
THROUGH THE 23RD/06Z...VFR WILL PREVAIL AT THE EYW AND MTH
TERMINALS. BY THIS AFTERNOON...LIGHT AND VARIABLE SURFACE
WINDS...COMBINED WITH WESTERLY LOW TO MIDLEVEL FLOW...SHOULD ALLOW
FOR A CLOUD LINE EXTENDING EASTWARD ALONG THE ISLAND CHAIN. CURRENT
FORECAST SOUNDINGS INDICATED DRY AIR INTRUSION WILL LIMIT THE
ROBUSTNESS AND PRECIPITATING ABILITY OF THE CLOUD LINE.
&&
.CLIMATE...
ON THIS DATE IN KEYS CLIMATE HISTORY...IN 1997...AN F1 TORNADO
PRODUCED $150K IN DAMAGE AROUND MM 58.5 ON GRASSY KEY. ALSO ON THIS
DATE...IN 1985...THE DAILY RECORD WARM LOW TEMPERATURE OF 82F WAS
RECORDED. THIS IS TIED FOR THE WARMEST LOW TEMPERATURE EVER RECORDED
IN MAY. AND IN 1940...THE DAILY RECORD LOW TEMPERATURE OF 68F WAS
LAST RECORDED. CONSIDERING OUR NORMAL LOW TEMPERATURE IS 76F...THE
ALL TIME RECORD LOW FOR MAY 22ND IS ONLY 8 DEGREES BELOW NORMAL.
TEMPERATURE RECORDS IN KEY WEST DATE BACK TO 1872.
&&
.PRELIMINARY POINT TEMPS/POPS...
KEY WEST 87 77 87 77 / 30 20 20 20
MARATHON 90 78 90 78 / 30 20 20 20
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE.........JACOBSON
AVIATION/NOWCASTS.....CLR
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 220218
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
1018 PM EDT TUE MAY 21 2013
.DISCUSSION...
.CURRENTLY...
SKIES ARE PARTLY CLOUDY WITH TEMPERATURES HOVERING AROUND 80 DEGREES
ALONG THE FLORIDA KEYS THANKS TO A STEADY EAST TO SOUTHEAST WIND.
MEANWHILE...LOCAL RADARS ARE DETECTING ISOLATED SHOWERS AND A STRAY
THUNDERSTORM ON THE GULF WATERS NORTH OF THE MIDDLE KEYS...AS WELL
AS THE OUTER WATERS OF MAINLAND MONROE. SURFACE WISE...A WESTERN
ATLANTIC RIDGE LIES ACROSS NORTH FLORIDA AND INTO THE GULF COAST
REGION. ACROSS OUR MARINE DISTRICT...C-MAN STATION PLATFORM
OBSERVATIONS SHOW EAST TO SOUTHEAST WINDS OF 10 TO 15 KNOTS.
OTHERWISE...OUR EVENING SOUNDING REVEALS AN ABUNDANCE OF MOISTURE
(PWAT 1.62 INCHES) UP TO 700 MB BEFORE SIGNIFICANT DRYING ABOVE.
FURTHERMORE...NO STABLE LAYERS ARE EVIDENT UNTIL NEAR 500 MB...WHILE
A DECOUPLED LOW LEVEL EASTERLY FLOW IS OVERLAID BY A UNIDIRECTIONAL
AND INTENSIFYING WESTERLY FLOW ABOVE 700 MB.
.SHORT TERM (REST OF TONIGHT)...
A MID AND UPPER LEVEL SHORT WAVE IN NORTH CENTRAL FLORIDA THIS
EVENING...WILL TRANSLATE SLOWLY EASTWARD ALLOWING DRIER AIR TO
SLOWLY FILTER DOWNWARD INTO THE LOWER LEVELS OVER THE NEXT 12 TO 24
HOURS. BUT UNTIL THEN...PLENTY OF LOW LEVEL MOISTURE...LITTLE IF ANY
CONVECTIVE INHIBITION ALONG WITH SEVERAL BOUNDARIES EMANATING FROM
THE LARGE NEIGHBORHOOD LAND MASSES WILL PROVIDE THE THREAT FOR
BOUNDARY COLLISIONS. HENCE...20 TO 30 PERCENT RAIN CHANCES LOOK
REASONABLE FOR THE ISLAND CHAIN. OUTSIDE OF BOTH POTENTIAL HEAVY
DOWNPOURS AND OUTFLOW BOUNDARIES...LOW TEMPERATURES WILL HOLD IN THE
UPPER 70S UNDER MAINLY PARTLY CLOUDY SKIES.
&&
.MARINE...
OUR EVENING SOUNDING INDICATES EAST TO SOUTHEAST WINDS OF 12 AND 6
KNOTS AT 1 AND 2 THOUSAND FEET RESPECTIVELY. WITH THE WESTERN
ATLANTIC RIDGE EXTENDING INTO NORTH FLORIDA WEAKENING TOWARD
MORNING...EXPECT THE TYPICAL...ALBEIT MINOR WIND SURGE THIS EVENING
AND EARLY TONIGHT. THEREAFTER...GENTLE TO MODERATE EAST TO
SOUTHEAST WINDS SHOULD ABATE SIGNIFICANTLY BY MORNING WITH THE
SPLITTING OF THE RIDGE. OTHERWISE...ISOLATED TO OCCASIONALLY
SCATTERED SHOWERS AND THUNDERSTORMS ARE ANTICIPATED ON ALL KEYS
COASTAL WATERS.
&&
.AVIATION...
THROUGH 23/00Z...VFR IS EXPECTED TO PREVAIL AT THE ISLAND TERMINALS
THROUGH THE PERIOD. SURFACE WINDS WILL GRADUALLY BECOME DIFFUSE NEAR
DAYBREAK. TOMORROW AFTERNOON...REVERSE CU LINES WILL BE SUPPORTED BY
WESTERLY LOW TO MIDLEVEL FLOW AND AN UNCAPPED...AND UNSTABLE PROFILE
THROUGHOUT THE LOW LEVELS...MID LEVEL DRY AIR INTRUSION SHOULD KEEP
ANY SHOWER ACTIVITY THAT DOES DEVELOP IN CHECK HOWEVER. MODERATE
CONFIDENCE AT THIS TIME IN A DRY FORECAST WITH OCCASIONAL NARROW
CIGS DUE TO ISLAND CLOUD LINES.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE/FIRE/DIGITAL...APA
AVIATION/NOWCASTS............MSB
DATA ACQUISITION.............BWC
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 211842
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
245 PM EDT TUE MAY 21 2013
.DISCUSSION...
.CURRENTLY...
KBYX DETECTS ISOLATED SHOWERS THROUGHOUT THE FORECAST AREA. SKIES
OVER THE ISLAND CHAIN ARE PARTLY CLOUDY. WINDS OVER LAND ARE EAST TO
SOUTHEAST NEAR 10 MPH. C-MAN WINDS...ON AVERAGE...ARE SOUTHEAST NEAR
10 KNOTS. TEMPERATURES ARE IN THE MID TO UPPER 80S.
.SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)...
AN ATLANTIC RIDGE OF HIGH PRESSURE WILL EXTEND ACROSS NORTH FLORIDA
TONIGHT AND WEDNESDAY MORNING...BEFORE RETREATING EASTWARD WEDNESDAY
AFTERNOON. A WEAK PRESSURE PATTERN WILL PREVAIL WEDNESDAY NIGHT
THROUGH THURSDAY NIGHT. THE BEST CHANCE OF MEASURABLE RAINFALL IN
THE SHORT TERM PORTION OF THE FORECAST LOOKS TO BE WEDNESDAY
AFTERNOON DUE TO ISLAND CUMULUS CLOUD LINES DEVELOPING NEAR OR
DIRECTLY OVER THE FLORIDA KEYS.
.LONG TERM (FRIDAY THROUGH TUESDAY)...
A LARGE AREA OF HIGH PRESSURE OVER THE OHIO VALLEY WILL BUILD
SOUTHWARD DOWN THE FLORIDA PENINSULA FRIDAY THROUGH SUNDAY. AN
ATLANTIC RIDGE OF HIGH PRESSURE WILL EXTEND ACROSS THE SOUTHEASTERN
UNITED STATES SUNDAY NIGHT THROUGH TUESDAY. THE ANTICIPATED PRESENCE
OF A RELATIVELY DRY AIR MASS WILL LIMIT POPS TO SLIGHT CHANCE
CATEGORY FRIDAY THROUGH SUNDAY. THE SUNDAY NIGHT THROUGH TUESDAY
PORTION OF THE FORECAST WILL BE BASED ON CLIMATOLOGY.
&&
.MARINE...
MODERATE EAST TO SOUTHEAST BREEZES WILL PREVAIL ON ALL KEYS COASTAL
WATERS TONIGHT. NO ADVISORIES OR CAUTIONARY HEADLINES EXPECTED
TONIGHT THROUGH AT LEAST SATURDAY MORNING. A SMALL CRAFT ADVISORY
MAY BE REQUIRED FOR ALL KEYS COASTAL WATERS SATURDAY AFTERNOON. A
SMALL CRAFT ADVISORY WILL LIKELY BE REQUIRED FOR ALL KEYS COASTAL
WATERS SATURDAY NIGHT. A SMALL CRAFT ADVISORY WILL LIKELY BE
REQUIRED FOR THE COASTAL WATERS OF THE FLORIDA STRAITS SUNDAY AND
SUNDAY NIGHT. A SMALL CRAFT ADVISORY MAY BE REQUIRED FOR THE COASTAL
WATERS OF FLORIDA BAY...HAWK CHANNEL...AND THE GULF OF MEXICO SUNDAY
AND SUNDAY NIGHT.
&&
.AVIATION...
THERE MAY BE BRIEF MVFR CIGS AT EYW THROUGH THE MIDDLE OF THIS
AFTERNOON. MAY NEED TO INCLUDE VCSH IN THE NEAR TERM THERE DUE TO
WEAKENING SHOWERS CURRENTLY UPSTREAM...ALTHOUGH THESE FEW SHOWERS
ARE ALREADY SMALL IN AREAL COVERAGE. OTHERWISE...EXPECT
PREDOMINANTLY VFR CONDITIONS AT BOTH EYW AND MTH THIS EVENING AND
THROUGH THE OVERNIGHT PERIOD. WINDS WILL BE FROM THE EAST TO
SOUTHEAST AT OR AROUND 10 KNOTS.
&&
.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1875...THE HIGH
TEMPERATURE IN KEY WEST WAS ONLY 74 DEGREES. THIS IS A LONG-STANDING
DAILY RECORD FOR COOL MAXIMUM TEMPERATURE FOR MAY 21ST IN KEY WEST.
&&
.PRELIMINARY POINT TEMPS/POPS...
KEY WEST 77 87 77 87 / 20 30 20 20
MARATHON 79 89 78 89 / 20 30 20 20
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE/FIRE/DIGITAL...BS
AVIATION/CLIMATE/NOWCASTS....MR
DATA ACQUISITION.............BWC
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 211422
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
1025 AM EDT TUE MAY 21 2013
.DISCUSSION...
.CURRENTLY...
KBYX DETECTS WIDELY SEPARATED SHOWERS THROUGHOUT THE FORECAST AREA.
SKIES OVER THE ISLAND CHAIN ARE PARTLY CLOUDY. WINDS OVER LAND ARE
EAST TO SOUTHEAST NEAR 10 MPH. C-MAN WINDS...ON AVERAGE...ARE
SOUTHEAST AT 10 TO 15 KNOTS. TEMPERATURES ARE IN THE MID 80S.
.SHORT TERM (THIS AFTERNOON)...
IN THE LOW LEVELS OF THE ATMOSPHERE...AN ATLANTIC RIDGE OF HIGH
PRESSURE WILL EXTEND ACROSS NORTH FLORIDA THIS AFTERNOON. IN THE MID
TO UPPER LEVELS OF THE ATMOSPHERE...A TROUGH OF LOW PRESSURE WILL BE
CENTERED NEAR THE EAST COAST OF THE FLORIDA PENINSULA TODAY. THE 12Z
KKEY SOUNDING IS EXTREMELY UNSTABLE AND QUITE MOIST FOR THIS TIME OF
YEAR...WITH A PRECIPITABLE WATER VALUE JUST UNDER ONE AND THREE
QUARTERS OF AN INCH. ATMOSPHERIC MOISTURE WILL REMAIN CONSTANT THIS
AFTERNOON. RAIN CHANCES TODAY WILL BE HIGHER THAN NORMAL FOR THE
LATTER HALF OF MAY DUE TO THE VERY MOIST AND UNSTABLE AIR MASS IN
PLACE COUPLED WITH THE PRESENCE OF A MID TO UPPER TROUGH OF LOW
PRESSURE ALONG THE EAST COAST OF THE FLORIDA PENINSULA.
&&
.MARINE...
GENTLE TO MODERATE EAST TO SOUTHEAST BREEZES WILL PREVAIL ON ALL
KEYS COASTAL WATERS THIS AFTERNOON. NO ADVISORIES OR CAUTIONARY
HEADLINES EXPECTED TODAY THROUGH AT LEAST SATURDAY MORNING.
SUSTAINED NORTHEAST SURFACE WINDS OF 15 TO 20 KNOTS ARE POSSIBLE ON
ALL KEYS COASTAL WATERS SATURDAY AFTERNOON. A SMALL CRAFT ADVISORY
MAY BE REQUIRED FOR ALL KEYS COASTAL WATERS SATURDAY NIGHT.
&&
.AVIATION...
BRIEF MVFR CONDITIONS ARE POSSIBLE INTO LATE MORNING AT MTH DUE TO
A FEW SLOW MOVING SHOWERS CURRENTLY IN THAT VICINITY. ADDED THAT
INTO A RECENT TERMINAL FORECAST UPDATE. WILL NEED TO MONITOR LATER
RADAR TRENDS TO SEE IF THERE WILL AN EQUIVALENT THREAT TO EYW. FOR
NOW...HAVE KEPT VFR CONDITIONS ADVERTISED THERE. EVEN IF SUB-VFR
CONDITIONS DO THREATEN LATER...THEY SHOULD BE SHORT IN DURATION.
EXPECT EAST TO SOUTHEAST BREEZES AT OR BELOW 10 KNOTS.
&&
.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1935...THE HIGH
TEMPERATURE REACHED 91F IN KEY WEST...AND IN 1929...3.54 INCHES OF
RAIN WAS RECORDED IN KEY WEST. BOTH OF THESE ARE DAILY RECORDS FOR
MAY 21ST IN KEY WEST.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE/FIRE/DIGITAL...BS
AVIATION/CLIMATE/NOWCASTS....MR
DATA ACQUISITION.............VICKERY
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 211143 AAA
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS...UPDATED
NATIONAL WEATHER SERVICE KEY WEST FL
743 AM EDT TUE MAY 21 2013
.AVIATION...
EYW AND MTH TERMINALS THROUGH THE 22ND AT 12Z...THIS MORNINGS
REMAINING NOCTURNAL ACTIVITY WILL CONTINUE TO DISSIPATE AND WILL NOT
IMPACT EITHER TERMINAL. FORECAST SOUNDINGS INDICATE POTENTIAL
DEVELOPMENT OF AN AFTERNOON CLOUDLINE...MAINLY AFTER 18Z. ANY
CONVECTIVE TRIGGERS ACTING ON THIS CLOUDLINE WOULD INCREASE THE
CHANCE FOR PRECIPITATION AT EITHER TERMINAL. EAST SOUTHEASTERLY
SURFACE WINDS AT EYW AND MTH WILL AVERAGE UNDER 10 KNOTS.
&&
$$
AVIATION...CLR
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 210822
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
422 AM EDT TUE MAY 21 2013
.DISCUSSION...
.CURRENTLY...
RADAR DETECTS SCATTERED SHOWERS ACROSS THE FLORIDA STRAITS...
THE UPPER KEYS AND FLORIDA BAY...WITH ISOLATED SHOWERS FURTHER WEST
ACROSS THE GULF WATERS. SKIES ARE PARTLY CLOUDY ACROSS THE AREA...WITH
TEMPERATURES ALONG THE KEYS ISLAND CHAIN HOVERING IN THE UPPER 70S TO
NEAR 80 DEGREES...AND WINDS ON LAND FROM THE EAST TO SOUTHEAST AT 5
TO 10 KNOTS.
SURFACE ANALYSIS DEPICTS A LARGE SUBTROPICAL HIGH PRESSURE AREA OVER
THE WESTERN ATLANTIC...EXTENDING WESTWARD ACROSS CENTRAL FLORIDA INTO
THE CENTRAL GULF OF MEXICO. ALOFT...THE PRIMARY FEATURE OF INTEREST
FOR OUR REGION IS A SMALL BUT WELL-DEFINED MID/UPPER LEVEL TROUGH
WHICH REMAINS NEARLY STATIONARY OVER THE FLORIDA PENINSULA. MIMIC-TPW
SATELLITE IMAGERY SHOWS THE SOUTH FLORIDA AND KEYS REGION ESCONSCED
WITHIN A MOIST AIRMASS...AND THE MONDAY EVENING KEY WEST SOUNDING
DEPICTS A CONDITIONALLY UNSTABLE PROFILE WITH VERY LITTLE CONVECTIVE
INHIBITION...AND PWAT OF 1.64 INCHES.
.SHORT TERM (TODAY THROUGH THURSDAY)...
THE PESKY MID/UPPER LEVEL TROUGH WILL REMAIN PARKED ACROSS THE
FLORIDA PENINSULA TODAY AND TONIGHT...THEN BEGIN TO EDGE SLOWLY
EASTWARD ON WEDNESDAY. AT THE SURFACE THE ATLANTIC RIDGE WILL HOLD
IN PLACE THROUGH TONIGHT...THEN WEAKEN AND SHIFT EASTWARD ON
WEDNESDAY AS A MID LATITUDE SHORTWAVE TROUGH AND ASSOCIATED COLD
FRONT ADVANCE INTO THE MISSISSIPPI VALLEY. THE TROUGH ALOFT SHOULD
WEAKEN AND SHIFT NORTHEASTWARD WEDNESDAY NIGHT AND THURSDAY...AS IT
BECOMES ENTRAINED INTO THE LARGER MID LATITUDE TROUGH. A VERY WEAK
SURFACE PRESSURE PATTERN WILL PREVAIL ACROSS THE KEYS DURING THIS
TIME AS THE FRONTAL BOUNDARY STALLS ACROSS THE NORTHERN GULF.
FOR THE FORECAST...SCATTERED SHOWER ACTIVITY ALONG VARIOUS BOUNDARIES
MAY PERSIST AT LEAST INTO THE EARLY MORNING HOURS TODAY...THEN THIS
AFTERNOON THERE WILL BE SOME POTENTIAL FOR A CLOUD LINE TO DEVELOP AS
MODEL SOUNDINGS SHOW A MARGINALLY FAVORABLE WIND PROFILE WITH DECENT
LOW LEVEL MOISTURE AND LAPSE RATES. OUTFLOWS FROM MAINLAND CONVECTION
MAY INVADE THE WATERS NORTH OF THE KEYS LATER THIS AFTERNOON...POSSIBLY
INTERACTING WITH A CLOUD LINE LATE THIS AFTERNOON INTO THIS EVENING.
WILL NUDGE POPS UP TO 40 PERCENT FOR TODAY...AND MAINTAIN 30 PERCENT
TONIGHT.
ON WEDNESDAY...A DRIER AIRMASS MAY BEGIN TO FILTER IN ALOFT AS THE
MID/UPPER TROUGH BEGINS TO EDGE SLOWLY EASTWARD...BUT MODEL SOUNDINGS
INDICATE DECENT LOW LEVEL MOISTURE REMAINING IN PLACE WITH THE
POTENTIAL FOR A REVERSE CLOUD LINE TO DEVELOP AS LOW/MID LEVEL FLOW
BECOMES VERY LIGHT AND MOSTLY FROM THE WEST/SOUTHWEST. WILL NUDGE POPS
UP TO 30 PERCENT.
WEDNESDAY NIGHT AND THURSDAY...A SOMEWHAT DRIER AIRMASS COMBINED WITH
A VERY WEAK FLOW REGIME...INCREASING STABILITY ALOFT...AND POSSIBLY
SOME DEVELOPING LOW LEVEL INHIBITION (AS SHOWN IN FORECAST
SOUNDINGS) SHOULD RESULT IN JUST ISOLATED CONVECTIVE COVERAGE. WILL
MAINTAIN 20 PERCENT POPS FOR THOSE PERIODS.
LITTLE CHANGE TO TEMPERATURES THROUGH THE PERIOD...WITH HIGHS MOSTLY
IN THE UPPER 80S...AND LOWS IN THE UPPER 70S TO NEAR 80.
&&
.LONG TERM (THURSDAY NIGHT THROUGH MONDAY)...
A DRIER AIRMASS WILL MOVE INTO THE KEYS AND SOUTH FLORIDA THURSDAY
NIGHT AND FRIDAY...AS THE AREA COMES UNDER NORTHWEST FLOW ALOFT DUE
TO A FAIRLY DEEP MID LATITUDE TROUGH ADVANCING TO THE EASTERN
SEABOARD. MODEL TIME-HEIGHT CROSS SECTIONS SHOW SIGNIFICANT DRY AIR
INVADING DOWN INTO THE LOWER/MID LEVELS...WITH DEWPOINT DEPRESSIONS
OF 15-20C BETWEEN 850 AND 700 MB DURING THIS TIME. THE EXISTING 20
PERCENT POPS WITH A THUNDER MENTION MAY BE A BIT GENEROUS FOR
THURSDAY NIGHT THROUGH FRIDAY NIGHT...BUT WILL LEAVE THEM UNCHANGED
FOR NOW.
AS WE HEAD INTO THE WEEKEND...HIGH PRESSURE BUILDING ACROSS THE
EASTERN CONUS WILL INDUCE INCREASING NORTHEAST/EAST FLOW ACROSS THE
KEYS. THE AIRMASS WILL REMAIN RATHER DRY INITIALLY...BUT LOW LEVEL
MOISTURE SHOULD INCREASE SATURDAY NIGHT AND BEYOND AS THE FLOW
BECOMES QUITE BRISK. SEE NO REASON TO ADJUST THE LATER FORECAST
PERIODS EITHER...WITH CHANCE POPS RETURNING SUNDAY THROUGH MEMORIAL
DAY DUE TO INCREASINGLY MOIST EASTERLY FLOW. NO SIGNIFICANT CHANGE TO
TEMPS.
&&
.MARINE...
OVERNIGHT OBSERVATIONS AND THE EDGE OF A NEARBY ASCAT PASS INDICATE
A MODEST EAST-SOUTHEAST WIND SURGE IN PROGRESS ACROSS THE KEYS
WATERS...WITH SPEEDS UP AROUND 15 KNOTS AT TIMES AT SOME OF THE
PLATFORMS. WINDS SHOULD DECREASE DURING THE MORNING HOURS...BUT WILL
PROBABLY SURGE A BIT ONCE AGAIN THIS EVENING. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS WILL REMAIN A CONCERN AS WELL. A FEW
WATERSPOUTS WILL BE POSSIBLE THIS AFTERNOON AND AGAIN ON WEDNESDAY
NEAR SHORE AS THE LOW LEVEL WIND PROFILE SHOULD BE FAVORABLE. WINDS
SHOULD BECOME LIGHT FROM THE SOUTHEAST ON WEDNESDAY...AND A PERIOD OF
LIGHT/VARIABLE WINDS IS STILL EXPECTED FROM THURSDAY THROUGH FRIDAY.
NORTHEAST FLOW SHOULD BECOME ESTABLISHED ON SATURDAY...THEN INCREASE
SATURDAY NIGHT AND SUNDAY. NO HEADLINES ARE EXPECTED THROUGH
SATURDAY...BUT EXERCISE CAUTION OR EVEN A SMALL CRAFT ADVISORY MAY BE
NEEDED SATURDAY NIGHT AND BEYOND.
&&
.AVIATION...
THROUGH 22/06Z...THE SOUTHEASTERLY MEAN FLOW HAS FAVORED A NOCTURNAL
PEAK IN SHOWER ACTIVITY...WHICH SHOULD DWINDLE BY DAYBREAK. FORECAST
SOUNDINGS INDICATE THE DEVELOPMENT OF AN AFTERNOON CLOUD
LINE...MAINLY AFTER 18Z. ANY CONVECTIVE TRIGGERS ACTING ON THIS
CLOUDLINE COULD ENHANCE THE CHANCE FOR PRECIPITATION AT EITHER
TERMINAL...BUT FORECAST CONFIDENCE REMAINS POOR UNTIL THE 12Z
SOUNDING. EAST SOUTHEASTERLY SURFACE WINDS AT EYW AND MTH WILL
AVERAGE UNDER 10 KNOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
KEY WEST 87 78 87 77 / 40 30 30 20
MARATHON 90 78 90 77 / 40 30 30 20
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE.........JACOBSON
AVIATION/NOWCASTS.....CLR
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 210258
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
1058 PM EDT MON MAY 20 2013
.DISCUSSION...
THE ATMOSPHERE ACROSS THE FLORIDA KEYS UNDERWENT A SIGNIFICANT CHANGE
DURING THE LAST 24 HOURS OWING TO A COMBINATION OF FORCES ON BOTH
LARGE AND SMALL SCALES. FIRST...A SIGNIFICANT MOISTENING OCCURRED
THROUGHOUT THE TROPOSPHERE AS A DEEPER MOIST LAYER ADVECTED INTO THE
REGION FROM THE BAHAMAS. SECOND...SIGNIFICANT COOLING OCCURRED ALOFT
OWING TO LARGE-SCALE GEOPOTENTIAL HEIGHT FALLS ASSOCIATED WITH AN
AMPLIFYING AND DEEPENING TROUGH OVER THE SOUTHEASTERN UNITED STATES
AND FLORIDA PENINSULA. THESE CHANGES PRIMED THE ATMOSPHERE FOR
DEEP...MOIST CONVECTION...AWAITING ONLY SUFFICIENT LIFTING OF
BOUNDARY-LAYER PARCELS. SUCH WAS PROVIDED LATE THIS AFTERNOON AS
FLORIDA PENINSULAR SEA BREEZES INITIATED SHOWERS AND THUNDERSTORMS
WHICH SUBSEQUENTLY DRIFTED SOUTHWESTWARD OVER THE WATERS JUST NORTH
OF THE KEYS. THE CELLS GENERATED A COLD POOL AND OUTFLOW BOUNDARIES
WHICH INITIATED ADDITIONAL CELLS RESULTING IN NEARLY 100 PERCENT
MEASURABLE RAINFALL COVERAGE OVER THE MIDDLE AND UPPER KEYS. THE COLD
POOL WAS SIGNIFICANT...DROPPING THE AIR TEMPERATURE TO 72F AT BOTH
MARATHON AND SOMBRERO KEY DURING THE HEAVY DOWNPOURS EARLY THIS
EVENING. IN ADDITION...SHORT-LIVED WIND GUSTS OF 25-35 KNOTS IN
ASSOCIATION WITH STORMS AND OUTFLOW WERE PREVALENT THROUGHOUT MOST OF
THE MIDDLE AND EVEN THE LOWER KEYS.
AS OF LATE...A MORE DIFLUENT AND WARM EAST-SOUTHEASTERLY FLOW HAS
SURGED ACROSS THE SERVICE AREA...WHILE SHOWER AND STORM COVERAGE HAS
DIMINISHED...BUT NOT DISAPPEARED. A FEW NEW CELLS ARE POPPING OVER
THE BAY AND GULF WATERS NORTH OF THE MIDDLE KEYS...WITH SOME YOUNG
CELLS AROUND THE CAY SAL BANK AS WELL. AIR TEMPERATURES ARE HOLDING
NEAR 80F IN COMMUNITIES WHERE NO RAIN FELL...AND HAVE REBOUNDED TO
77-79F EVEN WHERE HEAVY DOWNPOURS WERE OCCURRING JUST A FEW HOURS
AGO. FORECASTS HAVE ALREADY BEEN UPDATED A FEW TIMES OWING TO THE
RAPIDLY CHANGING CONVECTIVE SITUATION. WE HAVE KEPT OVERNIGHT SHOWER
COVERAGE SCATTERED WITH ISOLATED THUNDERSTORMS. LARGE-SCALE VERTICAL
MOTIONS CLEARLY ARE EITHER NEUTRAL OR WEAKLY UPWARD AT THIS TIME...
SO ALL THAT IS NEEDED FOR INITIATION IS A BOUNDARY-LAYER CONVERGENCE
OF MODEST INTENSITY...AND THERE ARE A PLETHORA OF THOSE AROUND THE
SERVICE AREA THIS EVENING.
&&
.MARINE...
EAST TO SOUTHEAST BREEZES HAVE BOTH RESUMED AND SURGED AT MOST
PLATFORMS...COMING IN AT A STEADY 15 KNOTS WITH HIGHER GUSTS AT LAST
CHECK. OVERNIGHT FORECASTS HAVE BEEN UPDATED FOR THE HIGHER WINDS AND
SEAS. A SLIGHT DECREASING TREND MAY COMMENCE LATE. SHOWER AND
THUNDERSTORM COVERAGE OVERNIGHT SHOULD BE HIGHER THAN THAT WHICH HAS
BEEN OBSERVED OVER THE LAST SEVERAL NIGHTS.
&&
.AVIATION...
THROUGH 22/00Z...A LATE-EVENING LULL IN SHOWER ACTIVITY SHOULD
PERSIST UNTIL AT LEAST 06Z AS THE ATMOSPHERE HAS BEEN SUFFICIENTLY
STABILIZED BY EARLIER CONVECTION. THEREAFTER...VFR SHOULD DOMINATE THE
FORECAST...THOUGH THERE WILL BE AN CONTINUAL CHANCE OF MVFR TO IFR
CONDITIONS IN BRIEF SHOWER ACTIVITY. CONFIDENCE IN EXACT TIMING OF
SHOWERS IS VERY LOW.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE.........KASPER
AVIATION/NOWCASTS.....MSB
DATA COLLECTION.......BWC
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 201905
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
305 PM EDT MON MAY 20 2013
.DISCUSSION...
ISOLATED TO SCATTERED SHOWERS THAT HAD BEEN FAVORING THE EASTERN HALF
OF THE KEYS SERVICE AREA HAVE BECOME MORE WIDELY SPACED OVER THE PAST
HOUR OR SO...WHILE STRONG CONVECTION HAS BLOSSOMED OVER A BIG POTION
OF SOUTH FLORIDA. WINDS IN THE KEYS SERVICE AREA HAVE GENERALLY BEEN
GENTLE FROM THE EAST/SOUTHEAST...BUT MODERATED IN THE EASTERN MARINE ZONES
OVER THE PAST FEW HOURS. TEMPERATURES ARE IN THE UPPER 80S ALONG THE
ISLAND CHAIN.
FORECAST REASONING HAS NOT CHANGED SIGNIFICANTLY FROM THE PREVIOUS
FEW FORECAST CYCLES FOR THE KEYS ISLAND CHAIN AND SURROUNDING WATERS.
A TROUGH IN THE MID TO UPPER LEVELS EVIDENT ON WATER VAPOR IMAGERY IS
BEGINNING TO CUT OFF OVER NORTH FLORIDA. MIMIC IMAGERY IS ALSO
SHOWING A POCKET OF DEEPER MOISTURE IMMEDIATELY UPSTREAM FROM THE
KEYS. SO...ALTHOUGH CURRENT RADAR TRENDS SUGGEST OTHERWISE IN THE
IMMEDIATE TERM...FEEL COMFORTABLE KEEPING A CHANCE OF SHOWERS WITH A
FEW THUNDERSTORMS ESPECIALLY SINCE THERE WILL BE BOUNDARIES PUSHING
THROUGH THE AREA TONIGHT FROM THE MAINLAND CONVECTION IN CONJUNCTION
WITH THE DEEPER MOISTURE. WILL KEEP THIS CHANCE OF SHOWERS AND SLIGHT
CHANCE OF THUNDERSTORMS THROUGH TUESDAY AND TUESDAY NIGHT AS THE
GYRE ABOVE WEAKENS AND BEGINS TO TRANSLATE NORTHEAST IN RESPONSE TO
ANOTHER BROAD TROUGH SWINGING THROUGH HIGHER LATITUDES. WILL KEEP A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THE SECOND HALF OF
THIS WEEK...AND INCREASE THE SHOWERS BACK TO A CHANCE SUNDAY INTO
MEMORIAL DAY AS BROAD AND STRONGER HIGH SURFACE PRESSURE REBUILDS TO
OUR NORTH...MOISTURE INCREASES ON MODERATING AND DEEPER EASTERLY
FLOW...AND ANOTHER LOW AMPLITUDE MID LEVEL TROUGH IS EXPECTED TO
CROSS THE STATE. THOSE LATE PERIODS ALSO HAD THE SURFACE WINDS
INCREASED A FEW KNOTS IN THE GRIDDED ELEMENTS...BUT NOT AS HIGH AS
THE LATEST GFS HAS SUGGESTED. NO NEED TO MAKE MORE THAN MINOR TWEAKS
TO THE GRIDDED TEMPERATURES THROUGH THE NEXT SEVEN DAYS.
&&
.MARINE...
EXPECT SCATTERED SHOWERS AND A FEW THUNDERSTORMS OVER THE NEXT FEW
PERIODS IN ALL WATERS SURROUNDING THE FLORIDA KEYS. AWAY FROM THIS
ACTIVITY...GENTLE TO BRIEFLY MODERATE EAST TO SOUTHEAST BREEZES
SHOULD BE THE TREND. A WEAK PRESSURE PATTERN AT THE SURFACE WILL
ALLOW FOR LIGHTER AND MORE DIRECTIONALLY VARIABLE WINDS FROM LATE
WEDNESDAY THROUGH THE EARLY PART OF THE WEEKEND.
&&
.AVIATION...
MVFR CEILINGS ARE CONCEIVABLE AT MTH THIS AFTERNOON INTO THIS
EVENING. THIS POSSIBILITY IS NOT GREAT ENOUGH TO PLACE IN THE MTH
TERMINAL FORECAST AT THIS TIME. VFR CONDITIONS WILL PREVAIL AT EYW
AND MTH TONIGHT THROUGH AT LEAST TUESDAY MORNING. SUSTAINED EAST TO
SOUTHEAST WINDS NEAR 10 KNOTS ARE EXPECTED FROM JUST OFF THE SURFACE
TO ABOUT 8000 FEET.
&&
.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1932...3.83 INCHES OF RAIN
FELL AT KEY WEST INTERNATIONAL AIRPORT. THIS SET THE DAILY RECORD
FOR MAXIMUM RAINFALL MEASURED IN KEY WEST ON MAY 20TH...A RECORD
WHICH STILL STANDS 81 YEARS LATER. RAINFALL RECORDS AT KEY WEST DATE
BACK TO 1871.
&&
.PRELIMINARY POINT TEMPS/POPS...
KEY WEST 78 87 78 87 / 30 30 30 20
MARATHON 79 90 79 90 / 30 30 30 20
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE.........04
AVIATION/NOWCASTS.....BS
DATA COLLECTION.......BWC
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 201356
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
956 AM EDT MON MAY 20 2013
.DISCUSSION...
ISOLATED TO SCATTERED SHOWERS ARE MOVING NORTHWESTWARD THROUGH THE
ATLANTIC WATERS ADJACENT TO THE MIDDLE AND UPPER KEYS...ACROSS THE
ISLAND CHAIN INTO THE BAY AND ADJACENT GULF WATERS. LAYERED CLOUDS
ARE STARTING TO SHOW MORE PROMINENT BREAKS FROM JUST A FEW HOURS AGO
ALONG THE ISLAND CHAIN AND ADJACENT WATERS. WINDS ARE GENTLE FROM THE
EAST TO SOUTHEAST AS TEMPERATURES SLOWLY CLIMB THROUGH THE LOWER 80S.
EARLY MORNING VISIBLE SATELLITE IMAGES INDICATE THAT ADDITIONAL
BREAKS ARE EXPECTED IN THE LAYERED CLOUDS THROUGH THE AFTERNOON. THE
MORNING LOCAL SOUNDING SHOWS A MORE MOIST...UNSTABLE...AND
CONVECTIVELY UNINHIBITED AIRMASS IS NOW IN PLACE WHEN COMPARED TO THE
PREVIOUS FEW DAYS. WE EXPECT TO SEE SCATTERED SHOWERS THROUGH THE
DURATION OF THE AFTERNOON. AND A COUPLE THUNDERSTORMS CAN NOT BE
RULED OUT WITH A LOW AMPLITUDE MID LEVEL TROUGH NEARBY. SO...UNLESS
THE CLOUDS REMAIN STUBBORN OVER THE NEXT COUPLE OF HOURS...NO UPDATE
WILL BE ISSUED FOR THE ZONES THIS MORNING.
&&
.MARINE...
EXPECT NO CHANGES ON THE LATE MORNING MARINE UPDATE. AWAY FROM
SCATTERED SHOWERS AND A FEW THUNDERSTORMS...GENTLE TO BRIEFLY
MODERATE EAST TO SOUTHEAST BREEZES WILL CONTINUE ACROSS ALL WATERS
SURROUNDING THE FLORIDA KEYS OVER THE NEXT COUPLE OF FORECAST
PERIODS.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL AT EYW AND MTH THIS MORNING INTO EARLY
THIS AFTERNOON. MVFR OR LOWER CONDITIONS ARE CONCEIVABLE AT EYW AND
MTH FROM LATE THIS AFTERNOON INTO THIS EVENING. THIS POSSIBILITY IS
NOT GREAT ENOUGH TO PLACE IN THE TERMINAL FORECASTS AT THIS TIME.
VFR CONDITIONS WILL PREVAIL AT EYW AND MTH TONIGHT. SUSTAINED EAST
TO SOUTHEAST WINDS NEAR 10 KNOTS ARE EXPECTED FROM JUST OFF THE
SURFACE TO ABOUT 8000 FEET.
&&
.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1875...THE HIGH
TEMPERATURE IN KEY WEST WAS ONLY 76 DEGREES. THIS SET THE DAILY
RECORD FOR COOLEST MAXIMUM TEMPERATURE EVER MEASURED IN KEY WEST ON
MAY 20TH...A RECORD WHICH STILL STANDS 138 YEARS LATER. TEMPERATURE
RECORDS AT KEY WEST DATE BACK TO 1872.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE.........04
AVIATION/NOWCASTS/CLIMATE.....BS
DATA COLLECTION.......VICKERY
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 201142
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
742 AM EDT MON MAY 20 2013
.AVIATION...
VFR CONDITIONS WILL PREVAIL AT THE KEY WEST AND MARATHON TERMINALS
THROUGH EARLY THIS AFTERNOON. SCATTERED SHOWERS WILL CONTINUE OVER
THE EASTERN FLORIDA STRAITS AND THE UPPER KEYS...BUT IT SEEMS UNLIKELY
THAT THIS ACTIVITY WILL DIRECTLY IMPACT THE TERMINALS. FROM MID
AFTERNOON THROUGH EARLY EVENING...FORECAST SOUNDINGS CONTINUE TO
SUGGEST THE POTENTIAL FOR A CLOUD LINE TO DEVELOP OVER OR JUST TO THE
NORTH OF THE KEYS ISLAND CHAIN. HAVE MAINTAINED A VCSH FOR BOTH
TERMINALS AFTER 20Z TO ACCOUNT FOR THIS POSSIBILITY...BUT THERE
REMAINS MUCH UNCERTAINTY AS TO WHETHER CONVECTION WILL DIRECTLY
IMPACT EITHER TERMINAL. SURFACE WINDS WILL REMAIN FROM THE EAST TO
SOUTHEAST AT 5 TO 10 KNOTS.
&&
$$
AVIATION...JACOBSON
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
000
FXUS62 KKEY 200633
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
230 AM EDT MON MAY 20 2013
.DISCUSSION...IN THE MID AND UPPER LEVELS...LATEST AVAILABLE IR
SATELLITE IMAGERY OVERLAID WITH MODEL STREAMLINES AS OF 200 AM
DEPICT A ROBUST COLD CORE MID AND UPPER CYCLONE POSITIONED OVER THE
ROCKY MOUNTAINS AND PLAINS STATES. JUST DOWNSTREAM OF THIS
FEATURE...EXCELLENT UPPER DIVERGENCE IS INDICATED OVER
IOWA...ILLINOIS AND MISSOURI THIS MORNING. AND WELL SOUTH OF THIS
FEATURE...A NEARLY ZONAL APPROX 50 KNOT JET AT 250 MB ROUNDS THE
BASE OF THE GYRE ACROSS NORTHERN OLD MEXICO AND TEXAS...WITH A WEAK
UPPER TROUGH AXIS IDENTIFIED DOWNSTREAM IN WITHIN THIS FLOW...WHICH
IS SITUATED ACROSS THE EASTERN GULF OF MEXICO...AND JUST UPSTREAM OF
THE FLORIDA PENINSULA.
AT THE SURFACE...LATEST AVAILABLE TROPICAL SURFACE ANALYSIS COMBINED
WITH AVAILABLE LAND AND MARINE OBSERVATIONS INDICATE THE WESTERN
PERIPHERY OF A 1020 MB SURFACE RIDGE EXTENDS TO ACROSS CENTRAL
FLORIDA FROM THE WEST CENTRAL ATLANTIC OCEAN. LAST EVENINGS 00Z
SOUNDING REVEALED A GENTLE MOSTLY EASTERLY FLOW FROM THE SURFACE TO
ABOUT 800 MB...WITH A MODERATELY DRY LOWER TO MID TROPOSPHERE AND
COLUMNAR PWAT AT 1.2 INCHES.
.CURRENTLY...AS OF 200 AM...SKIES ARE PARTLY CLOUDY GIVEN A
COMBINATION OF SOME HIGH CIRRUS AND SOME SCATTERED LOW CUMULUS
CLOUDS. KEY WEST RADAR DETECTS THE LEADING EDGE OF SMALL LOW TOPPED
SHOWERS ADVANCING WESTWARD IN THE EASTERN STRAITS. TEMPERATURES
ACROSS THE ISLANDS REMAIN NEAR 80 DEGREES WITH DEWPOINTS NEAR 70
DEGREES. WINDS ALONG THE FLORIDA REEF ARE EAST NEAR 10 KNOTS...WITH
ISLAND SENSORS RECORDING EAST WINDS NEAR 10 MPH.
.SHORT TERM (TODAY THROUGH TUESDAY NIGHT)...SLIGHTLY LOWER HEIGHTS
(AT 500 MB) WILL BE ASSOCIATED WITH THE AFOREMENTIONED APPROACHING
WEAK REGIONAL SCALE MID-LEVEL TROUGH...(NOW OVER THE EASTERN GULF OF
MEXICO). THIS FEATURE IS PROGGED TO LINGER NEAR THE KEYS TODAY
THROUGH AT LEAST TOMORROW NIGHT. BOTH AVAILABLE 00Z NAM AND GFS
MODEL FORECAST SOUNDINGS DO ILLUSTRATE SOME MOISTENING OF THE COLUMN
IN THE LOW TO MID TROPOSPHERE...WITH PWAT (PRECIPITABLE WATER)
RISING TO ABOVE 1.50 INCHES BY 12Z TODAY THROUGH TOMORROW EVENING
(06Z WED).
BUT DESPITE THIS UPSWING IN THE MOISTURE...WEAK SURFACE/LOW LEVEL
RIDGING SHOULD REMAIN NORTH OF THE KEYS...WHICH USUALLY MAINTAINS A
GENTLE EAST TO SOUTHEASTERLY FLOW ACROSS THE ISLANDS AND IS
GENERALLY NOT FAVORABLE FOR SHOWERS. HOWEVER...THE LATEST AVAILABLE
00Z MODEL SOUNDINGS HINT AT THE POSSIBLE DEVELOPMENT OF A CLOUDLINE
DURING THE LATER AFTERNOON AND EVENING HOURS LATE. AND THIS IS TRUE
TO A LESSER EXTENT AGAIN DURING TUESDAY AND TUESDAY EVENING. SO
THEREFORE WILL CONTINUE TO ADVERTISE SLIGHTLY ABOVE NORMAL CHANCES
FOR RAIN...OR A LOW CHANCE...(30 PERCENT) FOR SHOWERS WITH ISOLATED
THUNDERSTORMS THIS AFTERNOON AND EVENING THROUGH TUESDAY NIGHT.
DURING WEDNESDAY AND WEDNESDAY NIGHT...MODELS NOW INDICATE GREATER
MID LEVEL DRYING...WITH 00Z NAM AND GFS MODEL FORECAST SOUNDINGS
ILLUSTRATING PWAT ONLY BETWEEN 1.25 AND 1.50 INCHES. ON THE OTHER
HAND...THE SURFACE RIDGE IS ALSO PROGGED TO MOVE NEAR THE
KEYS...WHICH RESULTS IN LIGHT AND VARIABLE WINDS IN THE LOWER LEVELS
AND THE SURFACE. AND GIVEN THE POSITION OF THIS RIDGING
NEARBY...THERE IS A HINT THAT A REVERSE CLOUD LINE MAY DEVELOP. SO
FOR NOW WILL HOLD WITH 12 HOUR POPS NEAR CLIMO...WHICH IS AT 20
PERCENT.
EXTENDED...THURSDAY THROUGH SUNDAY...A WEAKLY CYCLONIC/MORE ZONAL
MID AND UPPER FLOW PATTERN IS INDICATED IN THE AVAILABLE
MODELS...(WITH LIGHT WINDS EXPECTED UP TO AT LEAST 500 MB). AT THE
SURFACE...WINDS WILL REMAIN LIGHT...GIVEN THE POSITION OF THE RIDGE
AXIS NEAR THE KEYS. HOWEVER...AVAILABLE 00Z MODEL FORECAST SOUNDINGS
ILLUSTRATE COLUMNAR PWAT ONLY AROUND 1.25 INCHES THROUGH THE PERIOD.
GIVEN THIS SETUP...ERRANT SOUTH FLORIDA MAINLAND AND CUBAN
BOUNDARIES CAN STILL IMPACT THE KEYS. SO WILL HOLD WITH THE 20
PERCENT WE ALREADY HAVE IN THE GRIDS FOR NOW...SLIGHT CHANCE FOR
ISOLATED SHOWERS AND THUNDERSTORMS.
&&
.MARINE...EXPECT GENTLE TO OCCASIONALLY MODERATE EAST/SOUTHEAST
BREEZES TO CONTINUE TODAY THROUGH TUESDAY NIGHT. WEAK RIDGING IS
ALSO PROGGED TO BE NEAR THE KEYS WEDNESDAY THROUGH THE REST OF THE
WEEK...RESULTING IN VARIABLE WINDS LESS THAN 10 KNOTS. THIS WILL
RESULT IN GENERALLY EXCELLENT BOATING CONDITIONS. SOME SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE WITHIN CUMULUS
CLOUD LINES NEAR THE SHORE THIS AFTERNOON AND EVENING...AND AGAIN ON
TUESDAY...WITH ONLY ISOLATED SHOWER AND THUNDERSTORM ACTIVITY
EXPECTED THEREAFTER.
&&
.AVIATION...VFR CONDITIONS WILL PREVAIL AT THE KEY WEST AND MARATHON
TERMINALS THROUGH EARLY THIS AFTERNOON. SCATTERED SHOWERS WILL
LIKELY BE PRESENT OVER THE FLORIDA STRAITS...BUT CONFIDENCE IN THIS
ACTIVITY DIRECTLY IMPACTING THE TERMINALS IS TOO LOW TO MENTION IN
THE TAFS AT THIS POINT. FROM MID AFTERNOON THROUGH EARLY
EVENING...FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR A CLOUD LINE
TO DEVELOP OVER OR JUST TO THE NORTH OF THE KEYS ISLAND CHAIN. HAVE
INCLUDED A VCSH FOR BOTH TERMINALS AFTER 20Z TO ACCOUNT FOR THIS
POSSIBILITY...BUT THERE REMAINS MUCH UNCERTAINTY AS TO WHETHER
CONVECTION WILL DIRECTLY IMPACT EITHER TERMINAL. SURFACE WINDS WILL
REMAIN FROM THE EAST TO SOUTHEAST AT 5 TO 10 KNOTS.
&&
.CLIMATE...ON THIS DATE IN KEYS WEATHER HISTORY...MAY 20TH IN
1932...THE DAILY RECORD RAINFALL OF 3.83" WAS RECORDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
KEY WEST 87 78 87 78 87 / 30 30 30 30 20
MARATHON 90 78 90 78 90 / 30 30 30 30 20
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE/FIRE/DIGITAL/CLIMATE...FUTTERMAN
AVIATION/NOWCASTS....................JACOBSON
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
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