SPC AC 280042
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0742 PM CDT TUE JUN 27 2006
VALID 280100Z - 281200Z
...THERE IS A SLGT RISK OF SVR TSTMS TONIGHT FROM CHESAPEAKE BAY NWD
INTO THE DE RIVER VALLEY...
...CHESAPEAKE BAY NWD THROUGH THE DE RIVER VALLEY...
SURFACE ANALYSIS SHOWS SURFACE LOW NEAR RWI WITH LATEST SHORT TERM
MODEL GUIDANCE INDICATING A CONTINUED NWD TRACK INTO ERN MD BY
28/12Z. AIR MASS ALONG AND E OF THIS LOW TRACK REMAINS QUITE MOIST
/PER 00Z WAL/ WHICH IS LARGELY CONTRIBUTING TO MLCAPES OF AROUND 800
J/KG. WHILE EXCESSIVE RAINFALL WILL REMAIN THE PRIMARY WEATHER
HAZARD ACROSS DISCUSSION AREA TONIGHT...THE PRESENCE OF MODEST LOW
AND DEEP-LAYER SHEAR /0-1 KM SRH OF AROUND 150 M2/S2 AND 0-6 KM SRH
OF 35 KTS/ SUGGEST A CONTINUED POTENTIAL FOR EMBEDDED SUPERCELLS
CAPABLE OF A BRIEF TORNADO OR TWO.
...WRN GREAT LAKES INTO THE LOWER MO VALLEY...
00Z REGIONAL SOUNDINGS AND WATER VAPOR IMAGERY INDICATE THAT STEEP
LOW/MID-LEVEL LAPSE RATES AND RESULTANT MODERATE INSTABILITY COUPLED
WITH SEVERAL IMPULSES DIGGING SEWD THROUGH THE REGION HAVE
CONTRIBUTED TO ONGOING TSTMS FROM ERN WI INTO CNTRL IL...MO AND NERN
KS. THESE STORMS SHOULD TEND TO WEAKEN OVER THE NEXT COUPLE OF
HOURS AS LOW-LEVEL LAPSE RATES WEAKEN AND INSTABILITY DIMINISHES.
HOWEVER...PRIOR TO THIS...STRONGEST STORMS WILL REMAIN CAPABLE OF
ISOLATED...SEVERE HAIL AND/OR LOCALLY STRONG WIND GUSTS.
...AZ...
TSTMS WHICH DEVELOPED EARLIER THIS AFTERNOON ALONG THE MOGOLLON RIM
APPEAR TO HAVE ORGANIZED A COLD POOL WITH THE LEADING EDGE OF THIS
FEATURE SURGING SSWLY INTO THE LOWER DESERTS. SRN AZ BOUNDARY LAYER
REMAINS HOT AND DEEPLY MIXED WITH LARGE TEMPERATURE-DEWPOINT SPREADS
OF 40-60 F. WHILE INSTABILITY IS NOT PARTICULARLY STRONG...ANY
STORMS THAT DEVELOP ALONG THE LEADING EDGE OF THIS CONVECTIVE
OUTFLOW WILL BE CAPABLE OF LOCALLY DAMAGING WINDS.
...NRN CA/NWRN NV...
WIDELY SCATTERED TSTMS HAVE DEVELOPED THIS AFTERNOON INTO EVENING
ALONG THE SIERRA NEVADA RANGE WITHIN WEAK MID-LEVEL DEFORMATION OR
SHEAR ZONE WHERE AIR MASS HAS BECOME SLIGHTLY TO MODERATELY
UNSTABLE. VERTICAL SHEAR REMAINS QUITE WEAK...HOWEVER DEEPLY-MIXED
BOUNDARY LAYER CONDITIONS WILL SUPPORT STRONG DOWNDRAFT POTENTIAL
WITH THE STRONGEST STORMS.
..MEAD.. 06/28/2006
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
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