DY1 SWODY1 01:01Z

0

VALID 040100Z – 041200Z

…THERE IS A SLGT RISK OF SVR TSTMS PORTIONS NM…SERN AZ…FAR W
TX…

…SYNOPSIS…
ANOMALOUSLY HIGH-AMPLITUDE PATTERN PERSISTS OVER CONUS…WITH
MID-UPPER LOW INVOF MKC ANCHORING DEEP/QUASISTATIONARY SYNOPTIC
TROUGH THAT EXTENDS FROM LS TO LOWER TX COAST AND SWRN GULF OF
MEXICO. ASSOCIATED CYCLONIC FLOW IS FLANKED BY STG RIDGING FROM
ATLC BERMUDA HIGH…AND FROM SMALLER BUT STILL STG ANTICYCLONE
CENTERED OVER S-CENTRAL/SWRN NV. LITTLE CHANGE IN OVERALL PATTERN
WILL TAKE PLACE THROUGH REMAINDER PERIOD…THOUGH WEAK HEIGHT FALLS
WILL OCCUR OVER PAC NW IN ADVANCE OF SHORTWAVE TROUGH NOW APCHG BC
COAST. VERY MINOR AND PROBABLY CONVECTIVELY GENERATED/ENHANCED
PERTURBATIONS SHOULD RIPPLE NWD ACROSS LOWER GREAT LAKES…OH VALLEY
AND SRN APPALACHIANS REGIONS…EMBEDDED WITHIN BROAD PLUME OF
DEEP-TROPOSPHERIC SLY FLOW.

SFC ANALYSIS AT 23Z SHOWED WAVY…REMNANT…FRONTOLYTIC…
QUASISTATIONARY BAROCLINIC ZONE FROM LOWER GREAT LAKES SSWWD ACROSS
CENTRAL KY AND MID TN TO SERN LA…THEN SWWD ACROSS SHELF WATERS
NEAR TX COAST. THIS BOUNDARY IS MANIFEST ANYMORE PRIMARILY BY WRN
FRINGE OF LOW-LEVEL MOISTURE PLUME…E OF WHICH DEW POINTS UPPER 60S
AND 70S F ARE VERY COMMON…AND W OF WHICH LOWER-THETAE CONTINENTAL
AIR MASS UNDERGOES GREATER NOCTURNAL-DIURNAL THERMAL OSCILLATIONS.
AS SUCH…AIR MASS WAS WARMER W OF FRONT…WITH CONSIDERABLE
CLOUDS/PRECIP TO ITS E HAVING LIMITED DIURNAL SFC WARMING.

…SRN ROCKIES/SRN HIGH PLAINS TO AZ…
SCATTERED TO WIDELY SCATTERED TSTMS…SOME SVR WITH AT LEAST
TRANSIENT SUPERCELLULAR CHARACTERISTICS…HAVE DEVELOPED OVER HIGHER
TERRAIN AND MOVED SWD TO SWWD AROUND SERN RIM OF NV ANTICYCLONE
ALOFT. TSTMS MAY MOVE INTO FAVORABLY MOIST/UNSTABLE BOUNDARY LAYERS
FOR A FEW MORE HOURS WITH RISK OF SVR GUSTS AND OCNL LARGE HAIL.
REF SPC WW 391 AND RELATED MESOSCALE DISCUSSIONS FOR LATEST
NEAR-TERM GUIDANCE. REF MESOSCALE DISCUSSION 1322 FOR INFORMATION
ON ADJOINING PORTIONS SERN AZ/SWRN NM. POTENTIAL BECOMES MORE
ISOLATED/CONDITIONAL FARTHER NW INVOF MOGOLLON RIM REGION.
OVERALL…SVR POTENTIAL ACROSS REGION SHOULD DIMINISH MARKEDLY BY
ABOUT 06Z…AS BOUNDARY LAYER BECOMES PROGRESSIVELY MORE STABLE DUE
TO COMBINATION OF SPREADING OUTFLOWS AND DIABATIC SFC COOLING.

…SERN CONUS…
LOOSELY ORGANIZED BANDS OF SCATTERED TO NUMEROUS TSTMS WILL CONTINUE
OVER PORTIONS TN VALLEY SWD TO MS/AL COASTAL PLAIN…AS WELL AS
ACTIVITY MOVING NWD TO NWWD ACROSS PORTIONS GA AND FL PANHANDLE.
ISOLATED DAMAGING GUSTS REMAIN POSSIBLE WHERE PRECIP-LOADING
ENHANCED DOWNBURSTS OCCUR…AND A TORNADO CANNOT BE RULED OUT
DEFINITIVELY GIVEN POCKETS OF AT LEAST MRGLLY FAVORABLE LOW-LEVEL
SHEAR. HOWEVER…SVR POTENTIAL IS LIMITED BY RELATIVELY
MESSY/CLUSTERED OR LINEAR STORM MODES…AS WELL AS INCREASING
COVERAGE OF PRECIP-STABILIZED AIR.

..EDWARDS.. 07/04/2013

Mesoscale discussion

0

Severe Storm Outlook Narrative for Sern Az..Extreme Swrn Nm concerning SEVERE POTENTIAL…WATCH POSSIBLE

Mesoscale discussion

0

Severe Storm Outlook Narrative for Cntrl-Srn-Ern Nm / Far Wrn Tx Panhandle concerning SEVERE POTENTIAL…WATCH POSSIBLE

Mesoscale discussion

0

Severe Storm Outlook Narrative for Nern Mt..Nwrn Nd concerning SEVERE POTENTIAL…WATCH UNLIKELY

Mesoscale discussion

0

Severe Storm Outlook Narrative for Locations Near And To The S-Sw Of Higher Terrain In Nm concerning SEVERE POTENTIAL…WATCH POSSIBLE

DY1 SWODY1 07:40Z

0

VALID 032000Z – 041200Z

…THERE IS A SLGT RISK OF SVR TSTMS ACROSS CNTRL/ERN GULF COAST
INTO SRN APPALACHIANS THIS AFTERNOON/TONIGHT…

…THERE IS A SLGT RISK OF SVR TSTMS FROM SERN AZ INTO SRN ROCKIES
THIS AFTERNOON/EVENING…

NO CHANGES REQUIRED TO 1630Z OUTLOOK. CONSIDERABLE AMOUNT OF
CONVECTION/PRECIPITATION PERSISTS WITHIN TROPICAL PLUME FROM THE ERN
GULF BASIN…NWD INTO THE SRN APPALACHIAN MOUNTAINS. WHILE AN
ISOLATED TORNADO CAN NOT BE RULED OUT…IT APPEARS HEAVY RAIN IS THE
PRIMARY THREAT WITH THIS ACTIVITY. ELSEWHERE…SCT TSTMS WILL ONCE
AGAIN EVOLVE/MATURE ACROSS THE SRN ROCKIES WHERE GUSTY WINDS MAY
ACCOMPANY THE STRONGEST ACTIVITY.

..DARROW.. 07/03/2013

.PREV DISCUSSION… /ISSUED 1117 AM CDT WED JUL 03 2013/

…SYNOPSIS…

LITTLE CHANGE TO THE LARGE-SCALE PATTERN IS FORECAST DURING THE D1
PERIOD. A HIGH-AMPLITUDE RIDGE-TROUGH-RIDGE CONFIGURATION WILL BE
MAINTAINED FROM THE SWRN CONUS TO WRN ATLANTIC WITH THE POLAR BRANCH
OF WESTERLIES CONFINED TO CANADA. WITHIN THIS BROAD-SCALE
REGIME…THE SLIGHT WWD RETROGRESSION OF THE WRN ATLANTIC HIGH WILL
ENHANCE THE MIDLEVEL HEIGHT GRADIENT FROM THE GULF COAST STATES
THROUGH THE TN VALLEY INTO LOWER GREAT LAKES. IN THE LOW LEVELS…A
N-S BAROCLINIC ZONE WILL REMAIN QUASI-STATIONARY FROM THE OH VALLEY
TO CNTRL GULF COAST…WHILE FARTHER TO THE NW A COLD FRONT SETTLES
SEWD THROUGH THE NRN HIGH PLAINS.

…CNTRL/ERN GULF COAST INTO SRN APPALACHIANS THIS
AFTERNOON/TONIGHT…

A CONFLUENT LOW-LEVEL FLOW REGIME WILL INTERACT WITH A VERY MOIST
AND POTENTIALLY MODERATELY UNSTABLE AIR MASS TO FOSTER NUMEROUS
TSTMS BY AFTERNOON ACROSS THE REGION. ELY/SELY SURFACE WINDS
BENEATH A STEADILY STRENGTHENING SLY MIDLEVEL WIND FIELD WILL RESULT
IN A VERTICALLY VEERING WIND PROFILE WITH SUFFICIENT VERTICAL SHEAR
FOR DEEP UPDRAFT ROTATION. THIS SETUP WILL BE SUPPORTIVE OF
EMBEDDED SUPERCELL STRUCTURES WITH A RISK FOR A COUPLE TORNADOES
GIVEN THE VERY MOIST/LOW LCL PBL. LOCALLY DAMAGING WINDS WILL ALSO
BE POSSIBLE OWING TO WATER LOADING OF CONVECTIVE DOWNDRAFTS.

…SERN AZ INTO SRN ROCKIES THIS AFTERNOON/EVENING…

SIMILAR TO PAST DAYS…DIURNALLY ENHANCED TSTM DEVELOPMENT IS
ANTICIPATED THIS AFTERNOON WITHIN A RELATIVELY STEEP LAPSE RATE AND
MODESTLY UNSTABLE ENVIRONMENT. SUFFICIENT /35-45 KT/ DEEP-LAYER
SHEAR WILL EXIST FOR SUPERCELLS AS THE INITIAL STORM MODE WITH A
RISK FOR HAIL AND LOCALLY DAMAGING WINDS. COALESCING COLD POOLS MAY
SUPPORT THE UPSCALE GROWTH OF STORMS BY THIS EVENING WITH AN
INCREASING RISK FOR DAMAGING WINDS.

…OH VALLEY INTO THE GREAT LAKES THIS AFTERNOON/EVENING…

A SURFACE LOW OVER NERN IL/NWRN IND WILL DEVELOP NWD TODAY IN TANDEM
WITH A VORTICITY MAXIMUM PIVOTING AROUND THE ERN PERIPHERY OF THE
PARENT UPPER LOW. THIS WILL CONTRIBUTE SCATTERED TSTM DEVELOPMENT
ACROSS THE NRN EXTENSION OF THE WARM SECTOR THIS AFTERNOON. GIVEN
THE COMBINATION OF MODEST AMOUNTS OF VERTICAL SHEAR AND
INSTABILITY…THE SETUP WILL BE SUPPORTIVE OF MULTICELL AND MARGINAL
SUPERCELLS CAPABLE OF SOME HAIL…LOCALLY DAMAGING WINDS…AND
PERHAPS A BRIEF TORNADO.

…NRN HIGH PLAINS THIS EVENING/TONIGHT…

LOW-LEVEL UPLIFT ALONG THE COLD FRONT COUPLED WITH THE GLANCING
INFLUENCE OF A SHORT-WAVE TROUGH AMPLIFYING OVER THE CANADIAN
PRAIRIE PROVINCES INTO NRN HIGH PLAINS WILL SUPPORT ISOLATED TO
WIDELY SCATTERED TSTM DEVELOPMENT MAINLY AFTER 04/00Z. SOME HAIL
AND/OR LOCALLY DAMAGING WINDS WILL ACCOMPANY THE STRONGEST STORMS.

…NRN SIERRAS INTO NRN ROCKIES THIS AFTERNOON/EVENING…

THE TRAILING EXTENSION OF THE PACIFIC COLD FRONT SETTLING SEWD
THROUGH THE PACIFIC NW IN CONJUNCTION WITH TERRAIN-INDUCED
CIRCULATIONS WILL FOSTER SCATTERED AFTERNOON TSTMS ON THE NRN
PERIPHERY OF GREAT BASIN MIDLEVEL ANTICYCLONE. LOCALLY DAMAGING
WIND GUSTS WILL BE POSSIBLE OWING TO STRONG EVAPORATIONAL COOLING
POTENTIAL WITHIN THE DEEP WELL-MIXED SUB-CLOUD LAYER.

DY1 SWODY1 04:19Z

0

VALID 031630Z – 041200Z

…THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL/ERN GULF COAST
INTO THE SRN APPALACHIANS…

…THERE IS A SLGT RISK OF SVR TSTMS SERN AZ INTO THE SRN ROCKIES…

…SYNOPSIS…

LITTLE CHANGE TO THE LARGE-SCALE PATTERN IS FORECAST DURING THE D1
PERIOD. A HIGH-AMPLITUDE RIDGE-TROUGH-RIDGE CONFIGURATION WILL BE
MAINTAINED FROM THE SWRN CONUS TO WRN ATLANTIC WITH THE POLAR BRANCH
OF WESTERLIES CONFINED TO CANADA. WITHIN THIS BROAD-SCALE
REGIME…THE SLIGHT WWD RETROGRESSION OF THE WRN ATLANTIC HIGH WILL
ENHANCE THE MIDLEVEL HEIGHT GRADIENT FROM THE GULF COAST STATES
THROUGH THE TN VALLEY INTO LOWER GREAT LAKES. IN THE LOW LEVELS…A
N-S BAROCLINIC ZONE WILL REMAIN QUASI-STATIONARY FROM THE OH VALLEY
TO CNTRL GULF COAST…WHILE FARTHER TO THE NW A COLD FRONT SETTLES
SEWD THROUGH THE NRN HIGH PLAINS.

…CNTRL/ERN GULF COAST INTO SRN APPALACHIANS THIS
AFTERNOON/TONIGHT…

A CONFLUENT LOW-LEVEL FLOW REGIME WILL INTERACT WITH A VERY MOIST
AND POTENTIALLY MODERATELY UNSTABLE AIR MASS TO FOSTER NUMEROUS
TSTMS BY AFTERNOON ACROSS THE REGION. ELY/SELY SURFACE WINDS
BENEATH A STEADILY STRENGTHENING SLY MIDLEVEL WIND FIELD WILL RESULT
IN A VERTICALLY VEERING WIND PROFILE WITH SUFFICIENT VERTICAL SHEAR
FOR DEEP UPDRAFT ROTATION. THIS SETUP WILL BE SUPPORTIVE OF
EMBEDDED SUPERCELL STRUCTURES WITH A RISK FOR A COUPLE TORNADOES
GIVEN THE VERY MOIST/LOW LCL PBL. LOCALLY DAMAGING WINDS WILL ALSO
BE POSSIBLE OWING TO WATER LOADING OF CONVECTIVE DOWNDRAFTS.

…SERN AZ INTO SRN ROCKIES THIS AFTERNOON/EVENING…

SIMILAR TO PAST DAYS…DIURNALLY ENHANCED TSTM DEVELOPMENT IS
ANTICIPATED THIS AFTERNOON WITHIN A RELATIVELY STEEP LAPSE RATE AND
MODESTLY UNSTABLE ENVIRONMENT. SUFFICIENT /35-45 KT/ DEEP-LAYER
SHEAR WILL EXIST FOR SUPERCELLS AS THE INITIAL STORM MODE WITH A
RISK FOR HAIL AND LOCALLY DAMAGING WINDS. COALESCING COLD POOLS MAY
SUPPORT THE UPSCALE GROWTH OF STORMS BY THIS EVENING WITH AN
INCREASING RISK FOR DAMAGING WINDS.

…OH VALLEY INTO THE GREAT LAKES THIS AFTERNOON/EVENING…

A SURFACE LOW OVER NERN IL/NWRN IND WILL DEVELOP NWD TODAY IN TANDEM
WITH A VORTICITY MAXIMUM PIVOTING AROUND THE ERN PERIPHERY OF THE
PARENT UPPER LOW. THIS WILL CONTRIBUTE SCATTERED TSTM DEVELOPMENT
ACROSS THE NRN EXTENSION OF THE WARM SECTOR THIS AFTERNOON. GIVEN
THE COMBINATION OF MODEST AMOUNTS OF VERTICAL SHEAR AND
INSTABILITY…THE SETUP WILL BE SUPPORTIVE OF MULTICELL AND MARGINAL
SUPERCELLS CAPABLE OF SOME HAIL…LOCALLY DAMAGING WINDS…AND
PERHAPS A BRIEF TORNADO.

…NRN HIGH PLAINS THIS EVENING/TONIGHT…

LOW-LEVEL UPLIFT ALONG THE COLD FRONT COUPLED WITH THE GLANCING
INFLUENCE OF A SHORT-WAVE TROUGH AMPLIFYING OVER THE CANADIAN
PRAIRIE PROVINCES INTO NRN HIGH PLAINS WILL SUPPORT ISOLATED TO
WIDELY SCATTERED TSTM DEVELOPMENT MAINLY AFTER 04/00Z. SOME HAIL
AND/OR LOCALLY DAMAGING WINDS WILL ACCOMPANY THE STRONGEST STORMS.

…NRN SIERRAS INTO NRN ROCKIES THIS AFTERNOON/EVENING…

THE TRAILING EXTENSION OF THE PACIFIC COLD FRONT SETTLING SEWD
THROUGH THE PACIFIC NW IN CONJUNCTION WITH TERRAIN-INDUCED
CIRCULATIONS WILL FOSTER SCATTERED AFTERNOON TSTMS ON THE NRN
PERIPHERY OF GREAT BASIN MIDLEVEL ANTICYCLONE. LOCALLY DAMAGING
WIND GUSTS WILL BE POSSIBLE OWING TO STRONG EVAPORATIONAL COOLING
POTENTIAL WITHIN THE DEEP WELL-MIXED SUB-CLOUD LAYER.

..MEAD/HART.. 07/03/2013

DY1 SWODY1 12:59Z

0

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

DY1 SWODY1 06:00Z

0

VALID 031200Z – 041200Z

…THERE IS A SLGT RISK OF SVR TSTMS ACROSS CENTRAL/SOUTHERN NM AND
SOUTHEAST AZ…

…SYNOPSIS…
TO THE SOUTH OF AN INCREASINGLY PROGRESSIVE BELT OF WESTERLIES OVER
CANADA…AN AMPLIFIED LARGE SCALE PATTERN WILL PERSIST OVER THE
CONUS THROUGH THE PERIOD. AN UPPER LOW WILL CONTINUE TO WEAKEN/SHIFT
WEST OF THE MS RIVER…FLANKED BY A BUILDING UPPER RIDGE OVER MUCH
OF THE EASTERN SEABOARD AND A SLIGHTLY WEAKENING WESTERN STATES
UPPER RIDGE.

…NM AND CENTRAL/SOUTHEAST AZ AND SOUTHERN CO…
INTO THIS AFTERNOON/EVENING…THE OVERALL PATTERN/SCENARIO OVER THE
REGION WILL HAVE CHANGED RELATIVELY LITTLE FROM TUESDAY…WITH A
RELATIVELY MOIST AIRMASS ACROSS THE REGION IN CONJUNCTION WITH
RELATIVELY STRONG NORTHERLY MID-HIGH LEVEL WINDS. AT LEAST WIDELY
SCATTERED IF NOT SCATTERED TSTMS ARE LIKELY TO DEVELOP/INCREASE
THROUGH THE AFTERNOON ACROSS PARTS OF CENTRAL/SOUTHERN CO AND
ESPECIALLY NM. SUFFICIENT SHEAR/DESTABILIZATION WILL EXIST FOR
SUSTAINED MULTICELLS/PERHAPS SOME BRIEF SUPERCELLS CAPABLE OF
ISOLATED INSTANCES OF SEVERE HAIL. BY LATE AFTERNOON…STORMS ARE
LIKELY TO CLUSTER/ORGANIZE INTO LINEAR BANDS WHILE PROPAGATING
SOUTH-SOUTHWESTWARD ACROSS THE SOUTHERN HALF OF NM AND PERHAPS ONTO
THE DESERT FLOOR OF SOUTHEAST AZ THROUGH EARLY/MID EVENING.

…SOUTHEAST STATES/APPALACHIANS…
WHILE UPPER HEIGHT RISES WILL CONTINUE TO OCCUR OVER THE REGION…A
RELATIVELY MOIST AIRMASS /NEAR OR ABOVE 70F SURFACE DEWPOINTS/ WILL
REMAIN ALONG/EAST OF A PERSISTENT NORTHEAST-SOUTHWEST ORIENTED
FRONTAL ZONE…BENEATH A MODERATE BELT /25-35 KT/ OF SOUTHERLY
MID-LEVEL WINDS. WIDELY SCATTERED SHOWERS/TSTMS WILL REMAIN QUITE
COMMON…WITH TSTMS MORE PREVALENT INTO THE AFTERNOON INCLUDING THE
POSSIBILITY OF SOME STRONGER/POSSIBLY SEVERE TSTMS CAPABLE OF
DOWNBURSTS. BUT…SIMILAR TO YESTERDAY…THE PROXIMITY OF THE UPPER
RIDGE/WEAK LAPSE RATES ALOFT AND RELATIVELY LIMITED DESTABILIZATION
SHOULD LIMIT THE OVERALL SCOPE/MAGNITUDE OF THE SEVERE RISK.

POTENTIAL FOR LOCALIZED WIND DAMAGE ASIDE…SOME TRANSIENT
SUPERCELLS AND POTENTIALLY ISOLATED/BRIEF TORNADO POTENTIAL WILL
EXIST THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF THE SOUTHEAST
STATES…ESPECIALLY IF LOW-LEVEL FLOW INDEED STRENGTHENS THIS
AFTERNOON INTO TONIGHT IN CONJUNCTION WITH A LOW ALONG THE GULF
COAST/INTERIOR SOUTHEAST STATES AS PROGGED BY VARIOUS 00Z-BASED
NUMERICAL GUIDANCE. EVEN SO…ANY SUCH POTENTIAL WILL LIKELY BE
TEMPERED BY TONIGHT VIA A SLIGHTLY COOLER NOCTURNAL BOUNDARY LAYER.

…MIDWEST/GREAT LAKES…
AS HAS BEEN THE CASE OVER THE PAST FEW DAYS…WEAK DESTABILIZATION
WILL OCCUR THIS AFTERNOON TO THE EAST-NORTHEAST OF A WEAK SURFACE
LOW AND IN VICINITY OF A WEAK/PERSISTENT FRONT AND/OR SURFACE
TROUGH. MODERATELY STRONG SOUTH-SOUTHWESTERLY MID-LEVEL WINDS WILL
CONTRIBUTE TO SUFFICIENT VERTICAL SHEAR FOR SOME SEMI-SUSTAINED
MULTICELLS AND PERHAPS A FEW TRANSIENT SUPERCELLS /MOST PROBABLE
ACROSS NORTHERN PORTIONS OF INDIANA AND OH INTO LOWER MI/. LOCALIZED
BOUTS OF WIND DAMAGE/MARGINALLY SEVERE HAIL WILL BE POSSIBLE THIS
AFTERNOON/EARLY EVENING IN AREAS FROM NEAR THE MIDDLE OH RIVER
VALLEY NORTHWARD INTO LOWER MI.

…GREAT BASIN/NORTHERN INTERMOUNTAIN REGION…
ANOTHER DAY OF WIDELY SCATTERED TSTMS ARE ANTICIPATED WITHIN A
RELATIVELY MOIST AIRMASS ON THE PERIPHERY OF THE FLATTENING UPPER
RIDGE. SOME OF THE STRONGER STORMS WILL BE CAPABLE OF DOWNBURSTS AND
POSSIBLY MARGINAL HAIL FROM THE SIERRA NEVADA EASTWARD INTO PARTS OF
ID/NORTHERN UT AND WY.

…NORTHEAST MT/WESTERN ND…
NEAR A SOUTHEASTWARD-ADVANCING FRONT…STORMS MAY DEVELOP
ACROSS/INTO PORTIONS OF NORTHEAST MT/WESTERN ND LATE THIS AFTERNOON
AND ESPECIALLY TONIGHT. SHOULD THIS OCCUR…ISOLATED BOUTS OF SEVERE
WINDS AND/OR HAIL WILL BE POSSIBLE.

..GUYER/LEITMAN.. 07/03/2013

DY1 SWODY1 01:00Z

0

VALID 030100Z – 031200Z

…THERE IS A SLGT RISK OF SVR TSTMS ACROSS SOUTHERN NM/SOUTHEAST
AZ…

…SOUTHERN NM/SOUTHEAST AZ…
ONGOING CLUSTERS/LINEAR BANDS OF STORMS WILL CONTINUE TO MOVE
SOUTH-SOUTHWESTWARD ACROSS SOUTHERN NM AND SOUTHEAST/CENTRAL AZ THIS
EVENING. LOCALLY STRONG/SEVERE WIND GUSTS WILL REMAIN POSSIBLE
THROUGH MID/PERHAPS LATE EVENING. REFERENCE MESOSCALE DISCUSSION
1318 FOR MORE DETAILS.

…OH VALLEY TO CAROLINAS/MID-ATLANTIC STATES…
WIDELY SCATTERED SHOWERS/TSTMS WILL CONTINUE THIS EVENING…BUT WITH
A DIMINISHING CONVECTIVE INTENSITY AS THE BOUNDARY LAYER COOLS.
TRANSIENT/WEAK SUPERCELL STRUCTURES MAY BE POSSIBLE THIS EVENING IN
AREAS SUCH AS THE CAROLINAS OR IN THE SHORT-TERM ACROSS NORTHERN
OH…BUT THE OVERALL DAMAGING WIND AND/OR BRIEF TORNADO RISK WILL
REMAIN QUITE MARGINAL THE REMAINDER OF THE NIGHT.

..GUYER.. 07/03/2013

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