VALID 031300Z – 041200Z

…THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF NM AND ERN AZ…

…THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL/ERN
GULF CST STATES…

…SYNOPSIS…
GRT BASIN ANTICYCLONE WILL GRADUALLY WEAKEN AND SETTLE A BIT SWD
THIS PERIOD AS ADDITIONAL PACIFIC SHORTWAVE IMPULSES TRACK ALONG ITS
NRN FRINGE INTO SW CANADA. FARTHER E…MS VLY/ERN PLNS TROUGH/LOW
SHOULD REMAIN NEARLY STNRY AS SEVERAL EMBEDDED SMALLER-SCALE
DISTURBANCES ROTATE AROUND IT…AND W ATLANTIC RIDGE CONTINUES
BUILDING WWD. ASSOCIATED TIGHTENING OF HEIGHT GRADIENT WILL YIELD
ANOMALOUSLY STRONG/DEEP SLY FLOW OVER THE OH AND TN VLYS AND
SOUTHEAST.

FEATURES WILL REMAIN WEAK AT THE SFC. DIFFUSE AREA OF LOW PRESSURE
NOW OVER THE N CNTRL GULF SHOULD BECOME BETTER DEFINED THROUGH THE
PERIOD AND DRIFT N TO THE CNTRL GULF CST BY 12Z THU AS ASSOCIATED
INVERTED TROUGH EXTENDS NNE INTO THE UPR TN VLY. ELSEWHERE…A WEAK
COLD FRONT AND LEE TROUGH ATTENDANT TO A PASSING SHORTWAVE TROUGH IN
CANADA WILL AFFECT THE NRN HIGH PLNS. THE ABOVE-MENTIONED SFC
FEATURES…IN ADDITION TO TERRAIN-INDUCED CIRCULATIONS IN THE WEST
AND VORT MAXIMA WITHIN THE CNTRL U.S. TROUGH…WILL YIELD POCKETS OF
STRONG TO POTENTIALLY SVR STORMS LATER TODAY THROUGH EARLY THU.

…NM/ERN AZ THIS AFTN INTO TNGT…
SOMEWHAT DRIER AIR HAS SPREAD SWD INTO NRN AZ AND NM SINCE
YESTERDAY…AND SATELLITE ATTM DOES NOT SUGGEST THE PRESENCE OF A
WELL-DEFINED UPSTREAM UPR IMPULSE TO FOCUS ASCENT ACROSS THE REGION
AS WAS THE CASE YESTERDAY. NEVERTHELESS…STRONG SFC HEATING AND
TERRAIN CIRCULATIONS AMIDST THE CONTINUING PRESENCE OF ANOMALOUSLY
STRONG/DEEP NLY FLOW SHOULD PROMOTE ANOTHER ROUND OF STRONG TO SVR
AFTN STORMS OVER THE NRN/CNTRL NM MOUNTAINS AND PERHAPS NE AZ. WIND
AND THERMODYNAMIC CONSIDERATIONS SUGGEST THIS ACTIVITY WILL ONCE
AGAIN MOVE/DEVELOP GENERALLY SSW IN THE FORM OF ONE OR MORE
CLUSTERS. THE STORMS COULD POSE A RISK FOR SVR HAIL /MAINLY DURING
THE EARLY STAGES OF DEVELOPMENT/ AND WIND/LOCAL HABOOB CONDITIONS
THROUGH EARLY TNGT.

…CNTRL GULF CST/SE U.S. TODAY THROUGH EARLY THU…
FAIRLY WIDESPREAD TSTM COVERAGE IS EXPECTED THROUGH THE PERIOD FROM
THE CNTRL/ERN GULF CST NNE INTO THE UPR TN VLY/SRN APPALACHIANS.
ACTIVITY WILL BE FOSTERED BY STRENGTHENING CONFLUENCE IN PLUME OF
VERY MOIST AIR /PWS AOA 2 INCHES/ ASSOCIATED WITH WWD-EXPANDING
ATLANTIC RIDGE. UPLIFT ALSO WILL BE FOCUSED ALONG AND NE OF NRN GULF
SFC LOW/TROUGH.

WHILE NEAR-SFC WINDS LIKELY WILL REMAIN WEAK…AS 850-700 MB LAYER
FLOW INTENSIFIES TO 30-40 KTS TNGT AND EARLY THU SETUP COULD YIELD
EMBEDDED LOW-LVL MESOS AND A RISK FOR TORNADOES…ESPECIALLY IN THE
FL PANHANDLE REGION AND PARTS OF GA/SE AL. IN THE NEAR-TERM…A MORE
LIMITED RISK FOR ISOLD TORNADOES COULD EVOLVE INVOF INVERTED TROUGH
OVER SE LA/SRN MS…WHERE SFC WINDS WILL REMAIN BACKED TO ELY
BENEATH MODEST SLY FLOW ALOFT.

…MIDWEST/GRT LKS THIS AFTN/EVE…
AS IN RECENT DAYS…DIURNAL HEATING SHOULD ONCE AGAIN FOSTER
CLUSTERS OF STORMS INVOF VORT MAXIMA AND ASSOCIATED AREAS OF
ENHANCED LOW-LVL CONVERGENCE ROTATING AROUND LARGER-SCALE UPR LOW
NOW CENTERED OVER NRN MO. SUCH ACTIVITY SHOULD BE MOST CONCENTRATED
IN AN ARC FROM NRN MO/IA EWD INTO PARTS OF IL/IND AND LWR MI.
SEASONABLY STRONG /35+ KT/ SSWLY MID-LVL FLOW WILL YIELD SUFFICIENT
DEEP SHEAR FOR SUSTAINED STORMS…INCLUDING MULTICELLS AND PERHAPS
TRANSIENT SUPERCELLS…ESPECIALLY IN NRN IND AND OH INTO LWR MI.
WHILE MOISTURE WILL BE A BIT LOW BY JULY STANDARDS /PW AROUND 1.25
INCHES AND SFC DEWPOINTS MAINLY IN THE LOW-MID 60S F/…SETUP COULD
PROMOTE LOCALIZED SVR WIND/HAIL IN THE MINIMALLY-CAPPED ENVIRONMENT
THROUGH EARLY EVE.

…NE MT/WRN ND THIS AFTN INTO TNGT…
AFOREMENTIONED COLD FRONT AND LEE TROUGH LIKELY WILL SERVE TO FOCUS
AFTN/EVE STORM DEVELOPMENT OVER NRN/ERN MT AND NW ND…WHERE
ADEQUATE MOISTURE…INSTABILITY…CONVERGENCE…AND SHEAR WILL EXIST
FOR A FEW SUSTAINED UPDRAFTS AND PERHAPS A SUPERCELL OR TWO.
COVERAGE MAY BE ISOLD BECAUSE OF SIZABLE EML CAP. BUT STORMS THAT DO
FORM COULD LINGER INTO EARLY THU IN WRN ND AND COULD PRODUCE FEW
INSTANCES OF SVR HAIL/WIND.

…GRT BASIN/NRN INTERMOUNTAIN REGION THIS AFTN/EVE…
SEVERAL AREAS OF DIURNALLY-ENHANCED TSTMS SHOULD ONCE AGAIN FORM ON
THE NRN AND WRN FRINGE OF NV UPR HIGH. SOME OF THIS ACTIVITY COULD
YIELD ISOLD DOWNBURSTS AND POSSIBLY MARGINAL HAIL…ESPECIALLY FROM
THE CA/NV SIERRA E/NE INTO PARTS OF ID…NRN UT…AND WY.

..CORFIDI/MOSIER.. 07/03/2013