Thursday, January 9, 2014

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 092000
SWODY1
SPC AC 091958

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0158 PM CST THU JAN 09 2014

VALID 092000Z - 101200Z

...NO SVR TSTM AREAS FORECAST...

...SRN-EAST CENTRAL FL...
GENERAL TSTM AREA HAS BEEN EXPANDED A LITTLE NWD ALONG THE EAST
CENTRAL FL COASTAL REGION FROM KVRB TO INVOF KMLB...GIVEN ONGOING
CONVECTIVE TRENDS IN THAT AREA.

...NRN UT...
AN ADDITIONAL LIGHTNING STRIKE OR TWO WILL BE POSSIBLE ACROSS NRN UT
WITHIN CORRIDOR OF STEEP LAPSE RATES/COLD MIDLEVEL TEMPERATURES
ATTENDANT TO A ESEWD MOVING SHORTWAVE TROUGH. OVERALL COVERAGE OF
THIS POTENTIAL IS NOT EXPECTED TO BE SUFFICIENT TO WARRANT THE
INCLUSION OF A 10 PERCENT TSTM AREA.

...SRN PLAINS TO ARKLATEX...
NO CHANGES NEEDED FOR THE GENERAL TSTM AREA FORECAST FOR LATE IN THE
PERIOD OVER PARTS OF TX INTO SOUTH CENTRAL OK TO THE ARKLATEX.

..PETERS.. 01/09/2014

.PREV DISCUSSION... /ISSUED 1029 AM CST THU JAN 09 2014/

...SYNOPSIS...
AN AMPLIFICATION TREND OVER THE CONUS...ONE THAT WILL PERSIST INTO
THE WEEKEND...WILL BEGIN LATER TODAY AS SHORTWAVE IMPULSE NOW
ADVANCING SE ACROSS THE NRN RCKYS/NRN GRT BASIN PHASES WITH SRN
STREAM DISTURBANCE NOW OVER BAJA CA/AZ TO YIELD A BROAD TROUGH OVER
THE HIGH PLNS BY 12Z FRI.

IN THE MEAN TIME...WEAKLY CYCLONIC ZONAL FLOW WILL CONTINUE OVER
MUCH OF THE NATION. TWO DISTURBANCES IN THIS PATTERN...ONE NOW OVER
THE ARKLATEX AND THE OTHER NOW ENTERING THE TX PANHANDLE...WILL
DOMINATE THE THUNDER FCST THIS PERIOD.

...TX HILL COUNTRY INTO ARKLATEX/SE OK TODAY/TNGT...
WAA/MOISTURE TRANSPORT SHOULD GRADUALLY INCREASE WITH TIME OVER THE
SRN PLNS/ARKLATEX...DOWNSTREAM FROM DEVELOPING UPR TROUGH AND ON
BACK SIDE OF RETREATING ARCTIC SFC RIDGE COVERING THE CNTRL AND ERN
U.S. OVERALL...HOWEVER...CURRENT OBSERVATIONS SUGGEST THAT MOISTURE
AVAILABILITY WILL REMAIN COMPARATIVELY MODEST OVER THE REGION...WITH
PW LIKELY REMAINING AOB 1 INCH UNTIL LATE IN THE PERIOD.

THUNDER POTENTIAL WITH BAND OF ELEVATED CONVECTION ATTM EXTENDING
FROM SE TX INTO ERN AR SHOULD CONTINUE TO DIMINISH TODAY AS THE
ASSOCIATED UPR IMPULSE NOW CROSSING THE ARKLATEX FURTHER WEAKENS AND
SYSTEM CONTINUES ENE INTO DRIER AIR. TSTM CHANCES
SHOULD...HOWEVER...INCREASE LATE IN THE PERIOD AS SSWLY LLJ OVER THE
SRN PLNS STRENGTHENS WITH THE APPROACH OF AMPLIFYING UPR TROUGH.
THIS SHOULD LEAD TO THE DEVELOPMENT OF ANOTHER ROUND OF POTENTIALLY
MORE ROBUST WARM CONVEYOR BELT CONVECTION...THIS ONE ORIENTED FROM
THE TX HILL COUNTRY NNE INTO S CNTRL/SE OK. SMALL HAIL MAY ACCOMPANY
THE STRONGER/MORE SUSTAINED UPDRAFTS...ESPECIALLY TOWARD 12Z FRI
OVER N TX AND THE RED RVR VLY...WHERE MUCAPE MAY REACH 750 J/KG AND
MODERATE TO STRONG UNIDIRECTIONAL CLOUD-LAYER FLOW WILL EXIST.

...SERN FL THIS AFTN...
OBSERVATIONS SHOW RESIDUAL SHALLOW COOL AIR LAYER CONTINUING TO
MODIFY OVER THE REGION...WITH ASSOCIATED SFC BOUNDARY BECOMING MORE
DIFFUSE OVER THE FL STRAITS. THESE TRENDS...ALONG WITH FURTHER
MOISTENING...SHOULD CONTINUE THROUGH THE PERIOD. MID-LVL LAPSE RATES
WILL REMAIN WEAK AND LARGE-SCALE FORCING FOR ASCENT NEGLIGIBLE. BUT
GIVEN VERY WEAK CINH DEPICTED IN LOCAL SOUNDINGS...COMBINATION OF
INCREASING MOISTURE...WEAK FRONTAL UPLIFT...AND MODEST SFC HEATING
MAY ALLOW EXISTING CONVECTION TO SUFFICIENTLY DEEPEN TO YIELD ISOLD
TO PERHAPS WDLY SCTD THUNDER LATER TODAY.

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