Post by SKYSUMMIT on Jan 24, 2015 1:36:41 GMT -6
A brief tornado is possible along the western Florida coast overnight:
MESOSCALE DISCUSSION 0040
NWS STORM PREDICTION CENTER NORMAN OK
0130 AM CST SAT JAN 24 2015
AREAS AFFECTED...COASTAL AREAS OF WEST-CENTRAL TO SOUTHWEST FL
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 240730Z - 241000Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...A MARGINAL THREAT FOR A BRIEF TORNADO EXISTS DURING THE
OVERNIGHT TO EARLY THIS MORNING ALONG THE WEST-CENTRAL /NEAR VENICE/
TO SOUTHWEST FL GULF COAST /IN VICINITY OF NAPLES/ WITH ANY
WATERSPOUTS THAT REACH THE COAST. GIVEN THE LOW THREAT AND LIMITED
SPATIAL EXTENT...A TORNADO WATCH ISSUANCE IS NOT WARRANTED.
DISCUSSION...AT 07Z...MOSAIC RADAR IMAGERY SHOWED A PRE-FRONTAL QLCS
EXTENDING SWWD FROM SARASOTA COUNTY THROUGH THE SERN GULF OF MEXICO
TO APPROXIMATELY 125 NM WNW EYW. THE ENVIRONMENT EAST OF THIS
CONVECTION TO COASTAL AREAS OF WEST-CENTRAL TO SOUTHWEST FL IS
MARGINALLY UNSTABLE /MUCAPE 500-900 J PER KG/ WITH SURFACE DEWPOINTS
AT OBSERVATION SITES ALONG THE COAST NEAR 70 F. DESPITE THE
MARGINAL INSTABILITY...EFFECTIVE BULK SHEAR OF 40-50 KT IS
SUFFICIENTLY STRONG TO SUPPORT SUSTAINED ROTATION AS HAS BEEN
OBSERVED WITH AT LEAST ONE STORM CURRENTLY MOVING ONTO THE COAST OF
SARASOTA COUNTY /NEAR 15-20 SM SSE SRQ/. VWP DATA PER TPA/EYW
WSR-88D/S AND OBJECTIVE MESOANALYSIS /EFFECTIVE SRH OF 200-300 M2
PER S2/ INDICATED LOW-LEVEL SHEAR /GIVEN SLY PRE-FRONTAL WINDS/
SUPPORTIVE OF LOW-LEVEL ROTATION. THIS IS CONFIRMED BY A PERSISTENT
LOW-LEVEL ROTATIONAL TRACK WITH THE SARASOTA COUNTY STORM PER
WDSS-II DATA.
THE ONGOING...AFOREMENTIONED...LINE OF STORMS SHOULD REACH THE FORT
MYERS AREA AROUND 09-10Z AND THEN INTO NAPLES AROUND 11Z. THE
FAVORABLE ENVIRONMENT FOR SPORADIC SUPERCELL STORMS TO POSSIBLY
PRODUCE WATERSPOUTS FROM OFFSHORE TO NEAR THE COAST SUGGESTS A BRIEF
TORNADO CANNOT BE RULED OUT ALONG THE COAST INTO EARLY SATURDAY
MORNING AS THE TSTM ACTIVITY ADVANCES EWD. A MORE STABLE
ENVIRONMENT FARTHER INLAND SHOULD LIMIT ANY SEVERE WEATHER THREAT
FROM AFFECTING LOCATIONS AWAY FROM THE COASTAL AREA.
..PETERS/EDWARDS.. 01/24/2015
MESOSCALE DISCUSSION 0040
NWS STORM PREDICTION CENTER NORMAN OK
0130 AM CST SAT JAN 24 2015
AREAS AFFECTED...COASTAL AREAS OF WEST-CENTRAL TO SOUTHWEST FL
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 240730Z - 241000Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...A MARGINAL THREAT FOR A BRIEF TORNADO EXISTS DURING THE
OVERNIGHT TO EARLY THIS MORNING ALONG THE WEST-CENTRAL /NEAR VENICE/
TO SOUTHWEST FL GULF COAST /IN VICINITY OF NAPLES/ WITH ANY
WATERSPOUTS THAT REACH THE COAST. GIVEN THE LOW THREAT AND LIMITED
SPATIAL EXTENT...A TORNADO WATCH ISSUANCE IS NOT WARRANTED.
DISCUSSION...AT 07Z...MOSAIC RADAR IMAGERY SHOWED A PRE-FRONTAL QLCS
EXTENDING SWWD FROM SARASOTA COUNTY THROUGH THE SERN GULF OF MEXICO
TO APPROXIMATELY 125 NM WNW EYW. THE ENVIRONMENT EAST OF THIS
CONVECTION TO COASTAL AREAS OF WEST-CENTRAL TO SOUTHWEST FL IS
MARGINALLY UNSTABLE /MUCAPE 500-900 J PER KG/ WITH SURFACE DEWPOINTS
AT OBSERVATION SITES ALONG THE COAST NEAR 70 F. DESPITE THE
MARGINAL INSTABILITY...EFFECTIVE BULK SHEAR OF 40-50 KT IS
SUFFICIENTLY STRONG TO SUPPORT SUSTAINED ROTATION AS HAS BEEN
OBSERVED WITH AT LEAST ONE STORM CURRENTLY MOVING ONTO THE COAST OF
SARASOTA COUNTY /NEAR 15-20 SM SSE SRQ/. VWP DATA PER TPA/EYW
WSR-88D/S AND OBJECTIVE MESOANALYSIS /EFFECTIVE SRH OF 200-300 M2
PER S2/ INDICATED LOW-LEVEL SHEAR /GIVEN SLY PRE-FRONTAL WINDS/
SUPPORTIVE OF LOW-LEVEL ROTATION. THIS IS CONFIRMED BY A PERSISTENT
LOW-LEVEL ROTATIONAL TRACK WITH THE SARASOTA COUNTY STORM PER
WDSS-II DATA.
THE ONGOING...AFOREMENTIONED...LINE OF STORMS SHOULD REACH THE FORT
MYERS AREA AROUND 09-10Z AND THEN INTO NAPLES AROUND 11Z. THE
FAVORABLE ENVIRONMENT FOR SPORADIC SUPERCELL STORMS TO POSSIBLY
PRODUCE WATERSPOUTS FROM OFFSHORE TO NEAR THE COAST SUGGESTS A BRIEF
TORNADO CANNOT BE RULED OUT ALONG THE COAST INTO EARLY SATURDAY
MORNING AS THE TSTM ACTIVITY ADVANCES EWD. A MORE STABLE
ENVIRONMENT FARTHER INLAND SHOULD LIMIT ANY SEVERE WEATHER THREAT
FROM AFFECTING LOCATIONS AWAY FROM THE COASTAL AREA.
..PETERS/EDWARDS.. 01/24/2015
