NWS /ISSUED 448 AM EST TUE FEB 3 2009/..COLDEST AIR OF THIS WINTER SEASON ARRIVING WED NIGHT…HARD FREEZE AND FREEZE WATCHES ISSUED FOR A LARGE PORTION OF MAINLAND SOUTH FL…
DISCUSSION…ONE COLD FRONT WILL EXIT THE AREA THIS MORNING. A FEW SHOWERS ARE SEEN ON RADAR OFF THE WEST CENTRAL FL COAST WITH SPRINKLES ACROSS PARTS OF THE AREA…SO ADDED JUST SLIGHT CHC LIGHT SHOWERS TO THE FCST FOR THIS MORNING. OTHERWISE…SKIES WILL CLEAR THIS AFTERNOON AS COLD HIGH PRESSURE BUILDS INTO THE AREA FROM THE NORTHWEST.
MUCH DRIER AIR WILL ARRIVE THIS EVENING WITH DEWPOINTS PLUMMETING INTO THE 30S. THIS WILL SET THE STAGE FOR A COLD NIGHT WITH 30S INLAND AND 40S AT THE COASTS.
THE SAVING GRACE FOR A FREEZE ACROSS INTERIOR AREAS TONIGHT LOOKS TO BE SLIGHT MOISTURE ADVECTION OVERNIGHT ESP JUST ABOVE THE SFC AND VEERING WINDS…ALBEIT LIGHT OVERNIGHT. THIS IS EXPECTED TO KEEP MINS FROM REACHING THE FREEZING MARK ACROSS N INTERIOR AREAS…THOUGH TRENDS WILL OF COURSE NEED TO BE WATCHED.
THE LUCK RUNS OUT TOMORROW NIGHT AS A DRY BUT VERY STRONG COLD FRONT RACES SOUTH OUT OF THE GREAT LAKES AND ACROSS SOUTH FL ON WEDNESDAY.
THIS FRONT LOOKS TO BRING THE COLDEST AIRMASS OF THIS WINTER SEASON TO THE AREA. 1000-850MB THICKNESSES ON THE LATEST GFS ARE NOTHING SHORT OF IMPRESSIVE…1293 AT THE LAKE TO 1306 AT MIAMI. THE LATEST ECMWF SHOWS 1299 AT THE LAKE TO 1311. ENSEMBLE MEAN VS. OPERATIONAL GFS FROM YESTERDAY (NEWEST NOT IN) WERE ACTUALLY WITHIN A FEW DEGREES OF EACH OTHER…LENDING TO HIGHER CONFIDENCE FOR THIS UPCOMING COLD/FREEZE EPISODE. THEREFORE…HAVE INITIATED HARD FREEZE AND FREEZE WATCHES FOR MUCH OF THE AREA FOR WED NIGHT/THU MORNING.
A FREEZE IS LIKELY INTERIOR…AND EVEN POSSIBLE ALL THE WAY TO THE GULF COAST. ON THE EAST COAST…THE TYPICAL COLDER LOCALES DURING COLD EVENTS SUCH AS THE REDLAND AND WEST KENDALL COULD SEE A FREEZE. FOR NOW THOUGH…MOST OF THE GOLD COAST SHOULD STAY ABOVE FREEZING…BUT TEMPS ARE EXPECTED TO FALL INTO THE 30S ALL THE WAY TO THE ATLANTIC COAST…AND WITH A NW WIND OF 10 TO 15 MPH…LOW WIND CHILLS WILL BE GENERATED…AS LOW AS THE MID TO UPPER 20S EVEN TO THE BEACHES. WIND CHILL HEADLINES WILL BE NEEDED AS THIS COLD EPISODE GETS CLOSER.
FOLLOWING ARE THE FORECAST LOW`S FOR THU 2/5 AND THE RECORDS:
FORECASTSRECORD
MIAMI 38 35 – 1958
FT. LAUDERDALE 38 31 – 1958
WEST PALM BEACH 34 33 – 1996
NAPLES 36 32 – 1996
SHOULD NOTE THAT IF TEMPS TREND LOWER NEXT 24 HR…THEN THE FREEZE WATCH WOULD NEED TO BE EXPANDED TO ENCOMPASS THE EAST COAST METROPOLITAN AREAS. CONFIDENCE WAS JUST NOT THERE TO INCLUDE THESE ZONES IN THE WATCH AT THIS TIME.
THE AIRMASS WILL TAKE TIME TO MODIFY…SO ANOTHER FREEZE IS POSSIBLE ACROSS NW INTERIOR AREAS AGAIN FRIDAY MORNING. TEMPS WILL MODERATE BY THE UPCOMING WEEKEND WITH TEMPS RETURNING BACK TOWARDS NORMAL…AND THEN EVEN ABOVE NORMAL FOR MUCH OF NEXT WEEK.