Funnel Cloud in Florida, July 20, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI
300 PM EDT SAT JUL 20 2002

LATEST SURFACE ANALYSIS SHOWS RIDGE CUTTING RIGHT ACROSS THE AREA.
IN FACT...THE RIDGE IS RIGHT OVER US AT LOW LVLS WITH THE AXIS
SHIFTING A BIT TO THE SOUTH PER 12Z UPR AIR DATA AND RUC ANALYSIS AT
MID LVLS. ABOVE H5 WE ARE BETWEEN AN UPR LVL TROUGH ACROSS THE EAST
COAST AND AN INVERTED TROUGH EXTENDING NE FROM THE WESTERN CARIBBEAN
THROUGH WESTERN CUBA AND THE NORTHERN BAHAMAS. THIS WHOLE SCENARIO
IS RESULTING IN VERY LIGHT WIND AT LOW LVLS WITH WINDS TURNING FROM
THE SW AT MID LVLS TO NE GREATER THAN 20 KNOTS ABOVE 350 MB OR SO.

12Z MODELS SEEM TO HAVE GOTTEN THIS PICTURE FAIRLY WELL. THE MAIN
CHANGE IN THE SYNOPTIC PATTERN AFTER ANALYZING MEDIUM AND SHORT
RANGE MODELS WILL BE THE UPR LVL RIDGE AXIS NORTH OF THE AREA MOVING
INTO THE AREA BY LATE IN THE EXTENDED WITH UPR LVL WINDS ROTATING
CLOCKWISE FROM NE NOW TO WESTERLY BY LATE IN THE EXTENDED AND
BECOMING LIGHTER. THIS IS IN RESPONSE TO UPR TROUGH TO THE NORTH
ALONG EAST COAST DIGGING FURTHER SOUTH BY EARLY IN THE WEAK, MONDAY
AND TUESDAY, BEFORE WEAKENING BY THE LATTER PART OF THE WEEK. IN
THIS REGARD I TEND MORE TO THE AVN THAN THE ETA. THE ETA DEVELOPS AN
UPR LVL LOW BY LATE TOMORROW ACROSS THE SE WHICH GIVEN CURRENT TREND
I DO NOT BUY ATTM. AT MID LVLS...THE RIDGE WILL REMAIN IN ITS
PRESENT POSITION, SLIGHTLY TO OUR SOUTH OR JUST ACROSS THE CWA
BEFORE SHIFTING SLIGHTLY NORTH OF THE CWA BY LATE IN THE EXTENDED.
AT THE SFC AND LOW LVLS, THE RIDGE WILL REMAIN ACROSS NORTHERN
SECTIONS OF THE CWA THROUGH WEDNESDAY THEN SHIFT JUST TO OUR NORTH
AND REMAIN THERE THROUGH THE END OF WEEK. MEDIUM RANGE GUIDANCE
WANTS TO DEEPEN SFC TROUGH ACROSS SE WED AND THU BUT WITH SYNOPTIC
SCALE FORCING WEAKENING BY THEN I WOULD NOT BUY INTO IT YET. AS FAR
AS MOISTURE GOES, PRECIPITABLE WATER REMAINS IN THE 1.7 TO 1.8 VCNTY
THROUGH THE EXTENDED.

SO WHAT DOES ALL THIS MEANS FOR THE FCST? FIRST OF ALL SYNOPTIC
SCALE FORCING ACROSS THE AREA REMAINS VERY WEAK. AS I SEE IT NOW WE
WILL REMAIN SLIGHTLY BELOW CLIMO AS FAR AS RAIN GOES THROUGH WEEKEND
AND THEN CLIMO THROUGH THE EXTENDED PARTICULARLY IN THE INTERIOR. AS
WE CONTINUE TO TRANSITION FROM A REGIME WITH A STRONG MID LVL RIDGE
EXTENDING INTO THE AREA FROM THE NW A FEW DAYS AGO TO MORE OF A
NORMAL SUMMER TIME PATTERN WITH WEAK UPR LVL FLOW AND LOW LVL RIDGE
EXTENDING FROM THE ATLANTIC, OUR TEMPS WILL COME SLIGHTLY DOWN TO
NEAR NORMAL LVLS BY MONDAY AND REMAIN THERE THROUGH THE WEEK. HIGHER
POPS WILL BE INTERIOR THRU 7 DAYS, AND WEST COAST LATE IN THE
EXTENDED. THIS IS ALSO EVIDENT IN FORECAST STORM MOTIONS FROM
DIFFERENT MODEL SOUNDINGS WHICH SHOW STORM MOTION VERY WEAK AT LESS
THAN 5 KNOTS FINALLY INCREASING FROM THE EASTERLY DIRECTION AT 5 TO
10 KNOTS BY THE END OF THE WEEK.

MARINE...MINOR CHANGES TO CURRENT PACKAGE WITH FLOW REMAINING AT OR
LESS THAN 10 KNOTS FROM THE SOUTH AND SE TURNING MORE FROM THE SE
END OF PERIOD WITH NORMAL DIURNAL CHANGE ALONG WEST AND EAST COASTS
ASSOCIATED WITH C-BRZS.

FIRE...NO HIGHLIGHTS.

.CRYSTAL FACE...PRELIM LOOK FOR SUNDAY, EXPECT MOSTLY MORNING
SHOWERS SHOWERS OVER BOTH EAST AND WEST COASTS, MOSTLY EAST, AND
INTO THE EARLY AFTERNOON.  THUNDERSTORM ACTIVITY SHOULD OCCUR MOSTLY
INLAND TRIGGERED BY BOTH COASTS SEA BREEZES AND OUTFLOW BOUNDARIES.
UPPER WINDS STILL AROUND 20 TO 30 KNOTS SO CIRRUS BLOWOFF WILL BE
TOWARDS THE SOUTHWEST. TOPS IN THE 45-50K FEET RANGE.

.MIA...NONE.

PBI BB 077/091 077/090 076 52232
FLL BB 078/090 078/089 078 52232
MIA BB 078/090 078/090 077 52232
APF BB 076/091 076/091 076 52131=

PS