SWODY1
SPC AC 011954
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0254 PM CDT THU JUL 01 2010
VALID 012000Z - 021200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS S TX...
...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT
FROM SWRN/CENTRAL MT INTO NWRN/NRN ND...
NO CHANGES ARE REQUIRED WITH THE ISSUANCE OF THIS CONVECTIVE
OUTLOOK...GIVEN THAT THE LATE MORNING FORECAST REMAINS ON TRACK FOR
THE TWO PRIMARY SEVERE WEATHER THREAT AREAS TODAY /NRN ROCKIES TO
NRN PLAINS AND S TX/. SHORT TERM MESOSCALE DETAILS FOR EACH OF
THESE REGIONS ARE AVAILABLE IN SPC MESOSCALE DISCUSSIONS 1176 FOR
NRN ROCKIES TO CENTRAL MT AND 1177 FOR TORNADO WATCH 435 ACROSS S
TX.
IN THE SOUTHEAST STATES...A COLD FRONT WILL CONTINUE TO SETTLE SWD
ACROSS SRN SC AND THROUGH MUCH OF GA/AL THIS FORECAST PERIOD. TSTM
CHANCES...THOUGH ALREADY LOW...WILL CONTINUE TO DIMINISH FROM N-S
WITH THE PASSAGE OF THE FRONT...AND THUS THE GENERAL TSTM LINE FROM
NRN AL TO THE SRN NC COAST HAS BEEN SHIFTED SWD.
..PETERS.. 07/01/2010
.PREV DISCUSSION... /ISSUED 1115 AM CDT THU JUL 01 2010/
...MT/ND AREA THROUGH TONIGHT...
SIMILAR TO YESTERDAY...A MIDLEVEL TROUGH REMAINS ANCHORED OVER THE
PAC NW...WITH A BELT OF 50-80 KT SWLY MID-UPPER FLOW EXTENDING
ACROSS ID/MT ALONG A LOW-MIDLEVEL BAROCLINIC ZONE. SOME MORNING
CONVECTION AND CLOUDS ACROSS S CENTRAL/CENTRAL MT ARE EXPECTED TO
CLEAR BY MIDDAY...WITH SUBSTANTIAL SURFACE HEATING IN THE WAKE OF
THESE CLOUDS. GIVEN MIDLEVEL LAPSE RATES NEAR 8 C/KM AND BOUNDARY
LAYER DEWPOINTS IN THE MID 50S...AFTERNOON MLCAPE VALUES OF
1500-2500 J/KG ARE EXPECTED.
ADDITIONAL THUNDERSTORM DEVELOPMENT SHOULD OCCUR BY 20-21Z OVER THE
HIGH TERRAIN IN SW/S CENTRAL MT. INSTABILITY AND EFFECTIVE BULK
SHEAR AOA 40 KT WILL AGAIN SUPPORT A FEW SUPERCELLS CAPABLE OF
PRODUCING ISOLATED VERY LARGE HAIL AND DAMAGING WINDS. THOUGH NOT
EXPECTED TO BE A PRIMARY THREAT...BOUNDARY LAYER MOISTURE AND
HODOGRAPH CURVATURE IN THE LOW LEVELS MAY ALSO BE SUFFICIENT FOR A
SUPERCELL TORNADO OR TWO THIS AFTERNOON/EVENING AS STORMS MOVE INTO
S CENTRAL/CENTRAL MT. LATER DURING THE EVENING...STORM MERGERS AND
COLD POOL INTERACTIONS COULD LEAD TO SOME UPSCALE GROWTH INTO ONE OR
MORE THUNDERSTORM CLUSTERS WITH A GREATER THREAT FOR DAMAGING WINDS
AS STORMS SPREAD NEWD ACROSS MT TOWARD WRN ND.
OTHER MORE ISOLATED THUNDERSTORM DEVELOPMENT WILL ALSO BE POSSIBLE
LATER THIS AFTERNOON/EVENING ALONG THE LEE TROUGH NEAR THE ERN WY
BORDER...AND FARTHER NE ALONG THE SUBTLE BAROCLINIC ZONE ACROSS ND.
ISOLATED DAMAGING GUSTS AND MARGINALLY SEVERE HAIL WILL BE THE MAIN
THREAT WITH ANY HIGH-BASED STORMS ALONG THE LEE TROUGH. A
LOW-PROBABILITY THREAT FOR ALL HAZARDS WILL ACCOMPANY ANY STORMS
FORMING ALONG THE FRONT IN ND WHERE INSTABILITY WILL BE STRONGER IN
AN ENVIRONMENT WITH MARGINALLY FAVORABLE LOW-MIDLEVEL SHEAR FOR
SUPERCELLS.
...S TX TODAY...
WEAKENING TC ALEX IS MOVING INLAND OVER MEXICO NEAR 23 N AND 100 W
AS OF 16Z. RICH MOISTURE AND A BELT OF 30-40 KT LOW-MIDLEVEL ESELY
FLOW EXTENDS AS FAR N AS S TX...WHERE REMNANT OUTER CONVECTIVE BANDS
ARE STILL ONGOING. A FEW SEMI-DISCRETE ROTATING STORMS AND A COUPLE
OF TORNADOES WILL STILL BE POSSIBLE THROUGH THE DAY WITHIN THESE
BANDS BEFORE VERTICAL SHEAR WEAKENS LATE TODAY INTO TONIGHT.
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