Wednesday, January 8, 2014

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 081936
SWODY1
SPC AC 081934

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0134 PM CST WED JAN 08 2014

VALID 082000Z - 091200Z

...NO TSTM AREAS FORECAST...

NO CHANGES NEEDED...SEE PREVIOUS DISCUSSION.

..PETERS.. 01/08/2014

.PREV DISCUSSION... /ISSUED 1026 AM CST WED JAN 08 2014/

...SYNOPSIS...
LARGELY ZONAL...WEAKLY CYCLONIC...MULTI-STREAM FLOW WILL PREVAIL
OVER THE CONUS THROUGH THU...S OF SLOWLY RETREATING POLAR VORTEX NOW
CENTERED OVER NRN LABRADOR. SHORTWAVE DISTURBANCES IN THE ZONAL
PATTERN WILL BE ACCOMPANIED BY A MODEST INCREASE IN CONVECTIVE
POTENTIAL OVER SEVERAL PARTS OF THE COUNTRY...BUT OVERALL
COMBINATION OF LIFT AND BUOYANCY IN THESE REGIONS LIKELY WILL REMAIN
TOO LIMITED TO POSE AN APPRECIABLE RISK FOR THUNDER.

...E TX/SE OK/ARKLATEX LATE TNGT/EARLY THU...
BOUNDARY LAYER AND LWR TROPOSPHERIC MOISTURE WILL CONTINUE TO
INCREASE THROUGH THE PERIOD FROM THE WRN GULF OF MEXICO NNE ACROSS E
TX INTO THE ARKLATEX...ON BACK SIDE OF RETREATING ARCTIC SFC RIDGE.
CURRENT SFC...925/850 MB...AND SATELLITE-DERIVED MOISTURE DATA
SUGGEST...HOWEVER...THAT MOISTURE RETURN WILL REMAIN TOO LIMITED TO
SUPPORT AN APPRECIABLE RISK FOR THUNDER GIVEN /1/ EXPECTED DEGREE OF
LARGE-SCALE FORCING FOR ASCENT DOWNSTREAM OF LOW-AMPLITUDE VORTS NOW
OVER NM AND W TX...AND /2/ RELATIVELY WARM TEMPERATURES ALOFT.

WHILE MODEST INCREASE IN LOW-LVL WAA/MOISTURE TRANSPORT SHOULD
SUPPORT A GRADUAL INCREASE IN ELEVATED CONVECTION OVER PARTS OF E
TX...SE OK...AND THE ARKLATEX...ESPECIALLY LATER IN THE PERIOD...THE
LIKELIHOOD FOR SIGNIFICANT COVERAGE OF TSTMS APPEARS LOW.

...S FL/KEYS TODAY/TNGT...
ARCTIC FRONT WILL BECOME STNRY AND INCREASINGLY DIFFUSE OVER THE
BAHAMAS/FL STRAITS/WRN CUBA LATER TODAY AS ASSOCIATED SFC RIDGE
EDGES E INTO THE ATLANTIC. THE BOUNDARY WILL BEGIN TO REFORM NWD
TNGT/EARLY THU...WITH THE 850 MB FLOW OVER THE REGION BECOMING MORE
SELY. THIS MAY LEAD TO INCREASING COVERAGE OF SHALLOW CONVECTION
ALONG AND N OF THE BOUNDARY...ESPECIALLY TNGT AND THU MORNING.
FORCING FOR ASCENT IN SRN STREAM JET WILL...HOWEVER...REMAIN WEAK.
COUPLED WITH COMPARATIVELY WARM AIR ALOFT...ANY THUNDER THREAT
SHOULD REMAIN CONFINED TO THE OFFSHORE WATERS WHERE LOW-LVL THETA-E
FLUXES WILL BE GREATEST.

...PAC NW THIS EVE...
MODERATELY STRONG SHORTWAVE IMPULSE NOW APPROACHING THE WA CST WILL
FURTHER AMPLIFY AS IT CONTINUES ESE ACROSS THAT STATE AND ORE
TNGT/EARLY THU. ISOLD/SPORADIC LTG MAY OCCUR THIS EVE IN ATTENDANT
CURRENT OF ONSHORE/UPSLOPE FLOW AND DCVA. HOWEVER...MUCAPE LIKELY
WILL REMAIN AOB 100 J/KG. IN ADDITION...THE DISTURBANCE DOES NOT
APPEAR PARTICULARLY STRONG IN CURRENT SATELLITE IMAGERY. THESE
FACTORS SUGGEST THAT THUNDER POTENTIAL REMAINS TOO MARGINAL FOR A
CATEGORICAL TSTM FCST.

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