NOAA's National Weather Service SPC Day 1, 2, 3 and 4-8 Convective Outlooks Update SPC Jul 28, 2010 2000 UTC Day 1 Convective OutlookWed, 28 Jul 2010 14:52:47 -0500 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0249 PM CDT WED JUL 28 2010 VALID 282000Z - 291200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE MIDWEST/LOWER GREAT LAKES TO NWRN NEW ENGLAND... ...THERE IS A SLGT RISK OF SVR TSTMS PARTS OF THE NRN GRT BASIN/INTERMOUNTAIN REGION... ...MIDWEST/LOWER GREAT LAKES TO NWRN NEW ENGLAND... NO MAJOR CHANGES NEEDED TO PREVIOUS FORECAST. MULTIPLE BANDS OF THUNDERSTORMS HAVE FORMED THIS AFTERNOON ALONG/AHEAD OF A SEWD MOVING COLD FRONT. THROUGH THIS EVENING...THE STRONGEST STORMS ARE EXPECTED TO AFFECT NE IND...NRN OH AND PERHAPS NW PA AND W NY. STORMS WILL BE EMBEDDED IN MODEST UNIDIRECTIONAL WLY FLOW REGIME. WHILE AN ISOLATED SUPERCELL IS POSSIBLE...PRIMARY STORM MODE WILL BE BOWING LINE SEGMENTS GIVING DAMAGING WIND GUSTS. ...NRN GREAT BASIN/INTERMOUNTAIN REGION... NO CHANGES TO PREVIOUS FORECAST. 18Z BOISE SOUNDING WAS CAPPED...OWING TO PASSAGE OF AN OUTFLOW BOUNDARY FROM MORNING PRECIPITATION. HOWEVER...ROBUST UPDRAFTS WERE DEVELOPING ON THE SOUTHWEST HIGHLANDS OF ID AND AIR MASS WILL CONTINUE TO DESTABILIZE...ESPECIALLY DOWNSTREAM OVER THE MAGIC VALLEY AND ADJACENT SAWTOOTH MOUNTAIN REGION. FARTHER W...AT LEAST ISOLATED THUNDERSTORMS WILL ALSO FORM ALONG THE TAIL-END OF THE DEPARTING SHORTWAVE TROUGH ACROSS SERN ORE AND TRANSLATE NWD ACROSS ERN ORE DURING THE EVENING. WIND FIELDS WILL BE MORE THAN ADEQUATE FOR ORGANIZED STORMS INCLUDING BRIEF SUPERCELLS AND BOW ECHOES CAPABLE OF LARGE HAIL AND DAMAGING WINDS...PARTICULARLY OVER ID. REST OF FORECAST REMAINS UNCHANGED. /JPR ..RACY/HALES/ROGERS.. 07/28/2010 .PREV DISCUSSION... /ISSUED 1105 AM CDT WED JUL 28 2010/ ...SYNOPSIS... LARGE SUMMERTIME UPPER HIGH DOMINATES MUCH OF U.S. WITH THE CENTER GRADUALLY DEVELOPING WWD ACROSS SRN PLAINS. SYSTEM MOVING EWD ACROSS SERN CANADA PROVIDING SOME HEIGHT FALLS AND STRONGER FLOW FROM GREAT LAKES TO NEW ENGLAND. LARGE SCALE TROUGH REMAINS OFF W COAST AS S/WV IMPULSE/VORT MAX MOVING NNEWD FROM CURRENT POSITION NRN CA THRU ERN ORE THIS AFTERNOON TO NRN ID/NWRN MT BY THU AM. ...MIDWEST/LWR GRT LAKES TO NWRN NEW ENGLAND THIS AFTN/EVE... COLD FRONT AT 16Z EXTENDS WSWWD FROM LH TO SRN WI...ACROSS NWRN KS TO ERN CO. VERY MOIST AIR MASS IS SPREADING EWD ACROSS OH VALLEY TO AS FAR E AS WRN NEW ENGLAND BY LATER TODAY IN ADVANCE OF THE COLD FRONT. WITH DAYTIME HEATING...INSTABILITY WILL ALSO INCREASE SUFFICIENTLY TO SUPPORT AN ORGANIZED BAND OF THUNDERSTORMS TO DEVELOP IN ASSOCIATION WITH THE FRONTAL CONVERGENCE. WHILE THE STRONGER FLOW WILL REMAIN GENERALLY N OF THE FRONT AND OVERALL LAPSE RATES WILL REMAIN WEAK...THE 30 KT OF MID LEVEL FLOW COUPLED WITH MLCAPES UPWARDS TO 2000 J/KG WILL FOSTER ORGANIZATION OF STORMS INTO BANDS. EMBEDDED BOWING SEGMENTS WILL BE CAPABLE OF DAMAGING WIND GUSTS FROM MID AFTERNOON THROUGH EARLY TONIGHT. GREATEST THREAT OF WIND DAMAGE VICINITY LE WHERE BETTER COMBO OF INSTABILITY/SHEAR WILL BE POSITIONED ALONG WITH ENHANCED CONVERGENCE OF THE LAKE BREEZE FRONT. ...NRN GREAT BASIN/INTERMOUNTAIN REGION THIS AFTERNOON/EVE... CONSIDERABLE GENERALLY WEAK CONVECTION HAS DEVELOPED IN ADVANCE OF NRN CA IMPULSE THIS MORNING IN RESPONSE TO ASSOCIATED LARGE SCALE ASCENT AND ELEVATED CAPES FROM 500-1000 J/KG. WITH HEATING... LAPSE RATES WILL STEEPEN AND STRENGTHEN THUNDERSTORMS BY MID AFTERNOON INCREASING THE LIKELIHOOD OF NOT ONLY LARGE HAIL BUT WIND DAMAGE POTENTIAL. SUFFICIENT DEEP LAYER SHEAR TO 40KT FOR STORM ROTATION WITH THE STRONGEST UPDRAFTS. THIS WOULD ENHANCE BOTH THE WIND AND HAIL POTENTIAL. BY MID AFTERNOON WHEN THE CONVECTIVE THREAT WOULD BE MAXIMIZED...VORT MAX WILL BE TRACKING NNEWD THRU ERN OR. HAVE EXTENDED THE SLIGHT RISK EWD INTO SERN ID GIVEN THE AVAILABLE MOISTURE/INSTABILITY MOVING NWD FROM UT/NERN NV...EVEN THOUGH SHEAR WILL BE A LITTLE WEAKER. ...TN VLY TO GA/CAROLINA'S... WITH A CONTINUED VERY MOIST AND POTENTIALLY UNSTABLE AIR MASS ACROSS THE AREA...SCATTERED DIURNAL STORMS WILL AGAIN OCCUR. GREATEST THREAT OF DOWNBURST WINDS WILL BE IN AREAS THAT HAVE THE LEAST MORNING CLOUD COVER TO IMPEDE THE HEATING PROCESS. SHEAR IS WEAK SO SVR THREAT WILL CONTINUE TO BE OF THE PULSE VARIETY. Read more To change your subscriptions or preferences or stop subscriptions anytime, log in to your User Profile with your e-mail address. For questions or problems with the service, contact support@govdelivery.com. This service is provided by NOAA’s National Weather Service. GovDelivery, Inc. (800-439-1420) sending on behalf of NOAA's National Weather Service · 1325 East West Highway · Silver Spring, MD 20910

Once our chances of rain end sometime Thursday -- and those are modest chances at best -- expect a sharp increase in heat that could bring parts of North Texas afternoon temperatures in the low 100s over the weekend and early next week.

The latest National Weather Service forecast discussion mentions possible temperatures of "103+" in some spots. Forecasters sum it up with, "Dry and much hotter this weekend through mid next week." Depending on how much moisture lingers in the air, heat advisories are possible, with the heat index potentially topping 110 in some places.

At this point, the hot forecast runs into the middle of next week. But forecasters note that at least a couple of computer models keep afternoon temperatures in the 100-degree range through next week, with mostly clear skies and very little chance of rain.

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