Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 281953
SWODY1
SPC AC 281952

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0152 PM CST SAT FEB 28 2015

VALID 282000Z - 011200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE POSSIBLE TODAY INTO
TONIGHT FROM THE CENTRAL CALIFORNIA COAST TO THE FOUR CORNERS
AREA...AND OVER PARTS OF SOUTH FLORIDA.  ORGANIZED SEVERE WEATHER IS
NOT EXPECTED.

THE ONLY CHANGE TO THE OUTLOOK IS TO MOVE THE THUNDER LINE ACROSS
THE CNTRL FL PENINSULA A BIT FURTHER NORTH TO ACCOUNT FOR ISOLATED
THUNDERSTORM ACTIVITY THAT IS ONGOING. OTHERWISE...NO CHANGES HAVE
BEEN MADE TO THE OUTLOOK FOR THE REMAINDER OF THE CONUS.

..BROYLES.. 02/28/2015

.PREV DISCUSSION... /ISSUED 1026 AM CST SAT FEB 28 2015/

...SYNOPTIC SETUP...
ELONGATED UPR LOW/TROUGH WILL CONTINUE TO SETTLE SLOWLY S ACROSS CA
AND THE FAR ERN PACIFIC THIS PERIOD. IN RESPONSE...EXPECT DOWNSTREAM
SPLIT FLOW TO GRADUALLY BACK AND HEIGHTS TO SLIGHTLY RISE ACROSS
MOST OF THE CENTRAL AND ERN U.S. WITH THE EXCEPTION OF THE FL
PENINSULA...ARCTIC OR MODIFIED ARCTIC AIR WILL PERSIST E OF THE
RCKYS. WARMER...BUT ONLY MODERATELY MOIST AIR OF RECENT PACIFIC
ORIGIN WILL PREVAIL OVER MUCH OF CA AND THE SOUTHWEST.

...CA TO FOUR CORNERS TODAY INTO TNGT...
SATELLITE SUGGESTS THAT THE MAIN VORT CENTER ASSOCIATED WITH E
PACIFIC/CA TROUGH WILL TRACK SWD OVER THE OFFSHORE WATERS.
NEVERTHELESS...A BAND OF MID-LVL COOLING/ASCENT WILL OVERSPREAD
CNTRL/SRN CA TODAY ATTENDANT TO ASSOCIATED VORT LOBE EXTENDING E
INTO THE CNTRL SIERRA. COUPLED WITH DAYTIME HEATING AND TERRAIN
CIRCULATIONS...SETUP SHOULD SUPPORT SCTD DIURNAL CONVECTION FROM THE
CNTRL CA CST ESE INTO THE CNTRL VLY/SRN SIERRA. SOME OF THIS
ACTIVITY WILL SUFFICIENTLY DEEPEN TO PRODUCE THUNDER AND PERHAPS
SMALL HAIL. BUT CONFIGURATION OF UPR TROUGH WILL LEAVE THE AREAS OF
GREATEST LOW-LVL DESTABILIZATION REMOVED FROM THE CORRIDORS OF DEEP
SHEAR MOST FAVORABLE FOR SVR STORMS. WHILE AN ISOLD FUNNEL CLOUD OR
HAIL REPORT CANNOT BE RULED OUT...SUSTAINED SVR WEATHER DOES NOT
APPEAR LIKELY. ELSEWHERE...WDLY SCTD AFTN/EARLY EVE SHOWERS/STORMS
ALSO MAY OCCUR E/SE TO THE FOUR CORNERS.

...SRN/CNTRL FL TODAY...
MARITIME TROPICAL AIR NOW OVER THE CARIBBEAN AND FL STRAITS WILL
GRADUALLY SPREAD N ACROSS THE SRN HALF OF THE FL PENINSULA THIS
PERIOD IN RESPONSE TO SLOWLY RISING HEIGHTS AND NWD RETREAT/EROSION
OF SHALLOW COOL DOME NOW EXTENDING S TO AROUND LK OKEECHOBEE.
LOW-AMPLITUDE SRN STREAM DISTURBANCE NOW OVER THE CNTRL GULF MAY
CONTINUE TO PRODUCE SUFFICIENT LOW-LVL WAA/MOISTURE TRANSPORT ATOP
COOL DOME TO YIELD ISOLD ELEVATED TSTMS IN THE TAMPA AREA TODAY.
FARTHER S...SFC-BASED STORMS MAY FORM IN RESPONSE TO DAYTIME HEATING
AND UPLIFT ALONG SHALLOW FRONT/CSTL TROUGH IN THE MIA/PBI AREA.
WHILE RELATIVELY HIGH PW MAY SUPPORT A STRONG DOWNDRAFT OR
TWO...WEAK WIND FIELD SHOULD PRECLUDE A SUSTAINED SVR THREAT.

...SE TX EARLY SUN...
STRENGTHENING 925-850 MB WAA/MOISTURE TRANSPORT AND ASSOCIATED
LOW-LVL CONFLUENCE AXIS MAY SUPPORT INCREASING COVERAGE OF SLIGHTLY
ELEVATED CONVECTION LATE IN THE PERIOD OVER SE TX. WITH NO UPSTREAM
UPR-LVL DISTURBANCE APPARENT ATTM IN SATELLITE IMAGERY TO PROVIDE
MID-LVL COOLING/ASCENT...AND WITH HEIGHTS EXPECTED TO SLOWLY RISE
WITH TIME...THE LIKELIHOOD THAT THE CONVECTION WILL SUFFICIENTLY
DEEPEN TO YIELD THUNDER APPEARS LOW. HOWEVER...A FEW...SPORADIC
LIGHTNING STRIKES MAY NEVERTHELESS OCCUR.




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