Severe Weather Outbreak? - July 8/9

[Dave]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0729 AM CDT WED JUL 08 2009

VALID 081300Z - 091200Z

...THERE IS A MDT RISK OF SVR TSTMS MUCH OF SOUTHERN NORTH DAKOTA
AND A LARGE PART OF SOUTH DAKOTA...

...THERE IS A SLGT RISK OF SVR TSTMS REMAINDER OF NRN PLAINS SWD TO
LWR MO VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS PARTS OF EASTERN GULF COAST
INCLUDING NRN FL...

...POTENTIAL FOR WIDESPREAD SEVERE THUNDERSTORMS PORTIONS OF THE
DAKOTAS LATE THIS AFTERNOON AND TONIGHT...


...SYNOPSIS...
A SIGNIFICANT S/WV TROUGH AND STRONG JET MAX CURRENTLY MOVING OUT OF
THE PREVAILING TROUGH POSITION OVER THE PAC NW. DOWNSTREAM RIDGE
AXIS NRN PLAINS SWWD TO UPPER HIGH SWRN TX SHIFTS SLOWLY
EWD...HOWEVER NWLY FLOW CONTINUES THRU THE PERIOD ERN PLAINS/MS
VALLEY.

SFC LOW INITIALLY CENTRAL WY MOVES INTO SWRN SD THIS AFTERNOON AND
LEE TROUGH SETS UP IN THE HIGH PLAINS LEADING TO SIGNIFICANT LOW
LEVEL MOISTURE ADVECTING NWD INTO DAKOTAS BY LATE THIS AFTERNOON.
COLD FRONT MOVES EWD ACROSS ERN MT/NRN WY INTO WRN DAKOTAS THIS
EVENING.

NERN UPPER LOW HAS DRIFTED SEWD TO NRN NY THIS AM AND FORECASTED NOW
TO OPEN INTO A TROUGH AND MOVE OFFSHORE TONIGHT. TRAILING PORTION
OF TROUGH SLOWLY MOVES ACROSS SERN STATES ENHANCING WLY FLOW ERN
GULF COAST WHERE A VERY MOIST AIR MASS IS IN PLACE.

...NRN PLAINS...
WITH THE APPROACH OF AN IMPRESSIVE MID/UPPER JET MAX ASSOCIATED WITH
THE TROUGH MOVING OUT OF THE NRN ROCKIES TODAY...IT NOW APPEARS THAT
WITH THE 850MB JET INCREASING TO 50KT BY 00Z...MOISTURE AND
INSTABILITY WILL BE IN PLACE TO SUPPORT A REGIONAL OUTBREAK OF
SEVERE STORMS IN THE DAKOTAS.

THUNDERSTORMS EXPECTED TO INITIATE BY MID AFTERNOON VICINITY OF COLD
FRONT ERN MT/NERN WY WHERE COMBINATION OF STEEP LAPSE RATES/STRONG
HEATING AND DEWPOINTS INTO THE 50S WILL HAVE GENERATED MLCAPES IN
EXCESS OF 2000 J/KG. GIVEN THE STRONG...VEERING SHEAR PROFILES
ASSOCIATED WITH THE S/WV TROUGH/WIND MAX...SUPERCELLS ARE LIKELY
DURING THE EARLY STAGES OF STORM DEVELOPMENT. VERY LARGE HAIL ALONG
WITH POTENTIAL FOR TORNADOES WOULD BE ASSOCIATED WITH ANY SUPERCELL.


THUNDERSTORMS ARE EXPECTED TO GROW UPSCALE INTO A SEVERE MCS AS THEY
MOVE INTO GREATER LOW LEVEL MOISTURE/INSTABILITY THAT WILL BE
AVAILABLE OVER THE DAKOTAS BY THIS EVENING. MODEL GUIDANCE SUPPORTS
POTENTIAL OF A DERECHO TYPE SCENARIO DEVELOPING EWD VICINITY SD/ND
BORDER EARLY TONIGHT WITH WIDESPREAD WIND DAMAGE. THIS ACTIVITY
SHOULD RIDE EWD ALONG NRN EDGE OF THE 700MB THERMAL RIBBON ACROSS
SD. ALONG WITH STRONG INSTABILITY...MLCAPES AOA 2500 J/KG...FEEDING
THE STORMS BY THIS EVENING...DCAPES AOA 1500 J/KG SUPPORT
DEVELOPMENT OF PRONOUNCED COLD POOL THAT WILL DRIVE THE POTENTIAL
DERECHO.

...LOWER MO VALLEY...
HAVE EXTEND THE POTENTIAL FOR AT LEAST ELEVATED SEVERE THRU TONIGHT
SWD INTO ERN KS/WRN MO. AS THE LOW LEVEL JET INCREASES THIS
EVENING...BOTH DEEP LAYER SHEAR AND ASCENT WITH WARM ADVECTION
SHOULD LEAD TO THUNDERSTORMS DEVELOPING AND MOVING SEWD AS MOISTURE
AND INSTABILITY SHOULD BE IN PLACE. PRIMARY THREAT WOULD BE LARGE
HAIL WITH WIND DAMAGE POSSIBLE IF STORMS CAN DEVELOP COLD POOLS.

..SERN STATES...
AS WEAK TROUGH DRIFTS EWD ACROSS SERN U.S....A BAND OF STRONGER
WESTERLIES WILL PREVAIL NRN FL. WITH A VERY MOIST TROPICAL AIR MASS
IN PLACE...PWS IN EXCESS OF 2 INCHES...THUNDERSTORMS WILL BE
SOMEWHAT MORE ACTIVE THAN USUAL FOR EARLY JULY. WITH ONGOING STORMS
AND CLOUDINESS ACROSS SRN GA/FL BORDER AREA...HAVE SHIFTED THE
THREAT FOR DAMAGING WINDS SWD SOME FOR TODAY.

..HALES/GARNER.. 07/08/2009

[Dave]

ZCZC SPCPWOSPC ALL
WOUS40 KWNS 081229
NDZ000-SDZ000-082030-

PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0729 AM CDT WED JUL 08 2009

...SEVERE THUNDERSTORMS EXPECTED OVER PARTS OF THE NORTHERN PLAINS
LATE AFTERNOON THROUGH TONIGHT...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
DEVELOPMENT OF WIDESPREAD DAMAGING WINDS OVER PARTS OF THE NORTHERN
PLAINS LATE AFTERNOON THROUGH TONIGHT.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE

CENTRAL AND SOUTHERN NORTH DAKOTA
MUCH OF SOUTH DAKOTA

ELSEWHERE...SEVERE STORMS ALSO ARE POSSIBLE FROM EASTERN MONTANA
ACROSS THE REMAINDER OF THE NORTHERN PLAINS THIS AFTERNOON AND
EVENING...AND SOUTHEASTWARD ACROSS PARTS OF THE LOWER MISSOURI
VALLEY REGION OVERNIGHT.

A MIDDLE-UPPER LEVEL TROUGH IS EXPECTED TO MOVE FROM THE PACIFIC
NORTHWEST ACROSS THE NORTHERN HIGH PLAINS THIS AFTERNOON AND
EVENING. MEANWHILE A RELATED COLD FRONT SHOULD PROGRESS EASTWARD
ACROSS THE DAKOTAS INTO A PROGRESSIVELY MORE MOIST AND UNSTABLE AIR
MASS. THUNDERSTORM POTENTIAL WILL REMAIN SUPPRESSED MOST OF THIS
AFTERNOON BY A STRONG CAPPING INVERSION OF WARM AIR ABOVE GROUND
LEVEL. NONETHELESS...BECAUSE OF THE FAVORABLE LEVELS OF
MOISTURE...INSTABILITY...LIFT AND WIND SHEAR...WE EXPECT THIS CAP TO
BREAK OVER PARTS OF THE NORTHERN HIGH PLAINS AND DAKOTAS...PERHAPS
AS EARLY AS LATE AFTERNOON.

SUPERCELLS WITH LARGE HAIL...SEVERE THUNDERSTORM WIND AND A FEW
TORNADOES ARE POSSIBLE AT FIRST. THEN...SEVERE STORMS SHOULD GET
MORE NUMEROUS THIS EVENING...GROWING INTO A COMPLEX WITH POTENTIAL
FOR A WIDESPREAD AND LONG-LASTING THUNDERSTORM WIND DAMAGE EVENT
KNOWN AS A DERECHO. THE GREATEST THREAT AREA APPEARS TO BE OVER
PARTS OF THE DAKOTAS. FOR MORE METEOROLOGICAL DETAILS PLEASE SEE
THE SPC CONVECTIVE DAY-1 OUTLOOK...WHICH IS BEING UPGRADED TO
WIND-BASED MDT RISK TO REFLECT THE THREAT.

STATE AND LOCAL EMERGENCY MANAGERS ARE MONITORING THIS DEVELOPING
SITUATION. THOSE IN THE THREATENED AREA ARE URGED TO REVIEW SEVERE
WEATHER SAFETY RULES AND TO LISTEN TO RADIO...TELEVISION...AND NOAA
WEATHER RADIO FOR POSSIBLE WATCHES...WARNINGS...AND STATEMENTS LATER
TODAY.

..EDWARDS.. 07/08/2009

[Dave]

Severe Weather Outbreak Possible Late Tonight into Thursday
A strong system will move into the Northern Plains late tonight into Thursday. Refer to the Storm Prediction Center Public Weather Outlook Here. This system will likely bring a round of severe thunderstorms to the region. Strong to severe storms will develop in western and central North Dakota late Wednesday afternoon and evening. These storms will then move quickly east tonight into eastern North Dakota, then into western Minnesota Thursday morning. The threat for widespread severe weather along with heavy rain is possible. Damaging winds may be the main threat late tonight into Thursday morning...so stay tuned to later forecasts and possible warnings on this upcoming severe weather and heavy rain potential. The timing of severe weather is detailed in the graphic below.



http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=fgf&storyid=29446&source=0

[Dave]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
314 AM CDT WED JUL 8 2009

.DISCUSSION...
THE MAIN CHALLENGE CONTINUES TO BE CONVECTIVE EPISODE FOR LATER
WED NIGHT INTO THU. MODELS ARE IN PRETTY GOOD AGREEMENT...WITH THE
NAM SLIGHTLY SLOWER AND PREFERRED SINCE THE FLOW IS STILL FAIRLY
BLOCKED. A STRONG SHORTWAVE AND UPPER JET STREAK IS NOW ENTERING
THE NORTHERN CA COAST...AND THIS WILL PROVIDE THE NEEDED KICKER TO
AID IN DEVELOPING CONVECTION TONIGHT INTO THU.

FOR TODAY...AN UPPER SHORTWAVE RIDGE WILL BUILD INTO THE REGION
WITH RETURN FLOW INCREASING. IT MAY BECOME BREEZY THIS AFTERNOON
WITH A TIGHTENING PRESSURE GRADIENT. THERE COULD BE A SLIGHT
CHANCE FOR A SHOWER/STORM IN THE FAR SOUTH AS A SHORTWAVE TROUGH
UNDERCUTS THE RIDGE. THERE WILL BE NO CONVERGENCE OR DEEP
LIFTING...SO FOR NOW WILL LEAVE IT DRY BUT MENTION TO DAYSHIFT.

FOR TONIGHT-THU...IT CONTINUES TO LOOK LIKE SEVERE CONVECTION
WILL MOVE THROUGH THE FORECAST AREA. MODEL TRENDS ARE SLOWING
DOWN THIS SYSTEM SLIGHTLY. IT APPEARS THAT SFC BASED STORMS WILL
FIRE THIS EVENING IN WESTERN ND NEAR A SFC TROUGH. THEREAFTER...MID
AND UPPER LEVEL WIND FIELDS WILL INCREASE RAPIDLY ACROSS ALL OF ND
INTO WESTERN MN BY 12Z THU. AN UPPER LEVEL JET AROUND 100KT WILL
ALSO PROVIDE STRONG UPPER LEVEL DIVERGENCE NEAR A SLIGHTLY COUPLED
JET STRUCTURE. PRECIPITABLE WATERS WILL INCREASE TO NEAR AN INCH
AT 00Z THU TO NEARLY 2 INCHES BY 12Z THU ALONG AND WEST OF THE
VALLEY. INSTABILITY WILL BE SUFFICIENT AS A SFC TROUGH AND
POSSIBLY AN AREA OF LOW PRESSURE MOVING INTO SE ND LATE
TONIGHT/EARLY THU MORNING. CAN/T RULE OUT ANY MODE OF SEVERE
WEATHER LATE TONIGHT/THU MORNING...EVEN ISOLATED TORNADOES...GIVEN
VERY STRONG SFC CONVERGENCE AND RAPID MOISTURE RETURN. THE MOST
LIKELY SCENARIO GIVING THE 0-6KM BULK SHEAR INCREASING TO NEAR
70KT LATE TONIGHT WILL BE RAPID THUNDERSTORM DEVELOPMENT NEAR
03-06Z IN WESTERN/CENTRAL ND. THESE STORMS WILL THEN MOVE QUICKLY
EAST INTO FAVORABLE MOISTURE/WARM ADVECTION INTO THE RED RIVER
VALLEY BY 12Z THU AND INTO THE EAST BY 18Z THU. WE EXPECT WIND
DAMAGE WILL LIKELY BE THE MAIN THREAT...AND A DERECHO IS POSSIBLE
(SOMEWHERE IN THE NORTHERN PLAINS) WITH STORM MOTION FROM 30-40KT
AND PROBABLY HIGHER NEAR INDIVIDUAL BOW ECHOES AND LEWPS.

HEAVY RAIN WILL BE POSSIBLE NEAR ANY STORM WITH VERY HIGH
PWATS...AND WITH THE FAST STORM MOTION WIDESPREAD FLOODING SHOULD
NOT BE A PROBLEM. FLASH FLOOD GUIDANCE VALUES ARE HIGH (OVER 3
IN/HR)...ALTHOUGH IF SEVERAL CLUSTERS MOVE OVER AN AREA THEN
WE/LL HAVE TO MONITOR. RIVERS ARE GOING DOWN AND THE SOIL CAN SOAK
UP SOME MOISTURE WITH CROPS PRIME TO ACCEPT RAIN...BUT IF AN AREA
QUICKLY GETS 1-3 INCHES OF RAIN THEN LOCALIZED PONDING AND
FLOODING OF URBAN AREAS IS ALWAYS A THREAT. WE WILL MENTION THREAT
IN THE HWO AND SEVERE WORDING IN THE GRIDS.

FOR THU NIGHT...CONVECTION WILL BE EAST OF THE AREA AND EXPECT
MUCH DRIER AIR TO ADVECT INTO THE AREA.

ON FRIDAY...THERE WILL BE THE CHANCE FOR AN ISOLATED AFTERNOON
STORM WITH CYCLONIC FLOW AND COOLER AIR ALOFT BUILDING INTO THE
REGION. INSTABILITY WILL BE MARGINAL...BUT LAPSE RATES WILL BE
SUFFICIENT TO PRODUCE A FEW STORMS BY AFTERNOON WITH TEMPS FALLING
BELOW NORMAL.

[Dave]

delete

[Dave]

MESOSCALE DISCUSSION 1486
NWS STORM PREDICTION CENTER NORMAN OK
1138 AM CDT WED JUL 08 2009

AREAS AFFECTED...MT...ND

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 081638Z - 081815Z

WELL-FORMED SUPERCELL TRACKING ACROSS MCCONE COUNTY/NERN MT APPEARS
TO BE TRANSITIONING INTO BOWING SEGMENT AND MOVING ENEWD AT 40KT.
THIS CELL/COMPLEX HAS TAKEN FORM NEAR/NORTH OF SURFACE LOW AND
QUASISTATIONARY BOUNDARY INTERSECTION THIS AREA. STORM UPDRAFTS ARE
LIKELY ROOTED JUST ABOVE THE SURFACE LAYER GIVEN GGW SOUNDING
ADJUSTED FOR CURRENT CONDITIONS AND LARGE HAIL HAS ALREADY BEEN
REPORTED WITH THE STORM. DESPITE RELATIVELY LIMITED SURFACE-BASED
INSTABILITY ACROSS NERN MT...IT APPEARS THAT STORM DYNAMICS ARE
BEING AIDED BY STRONG LARGE SCALE FORCING FOR ASCENT AND POTENT
DEEP-LAYER SHEAR ALONG AND NORTH OF CAPPED WARM SECTOR AIRMASS
SITUATED ACROSS MUCH OF ERN MT ATTM.

GIVEN SURFACE HEATING ACROSS WARM SECTOR OVER SERN MT AND WRN
ND...EXPECT INSTABILITY FEEDING INTO THIS REGION OF STRONG ASCENT
WILL ONLY CONTINUE TO INCREASE. ADDITIONAL ORGANIZED STORM
DEVELOPMENT APPEARS LIKELY OVER THESE AREAS INTO THE AFTERNOON AS
SHORT WAVE TROUGHS CONTINUE TO SPREAD EAST WITHIN BELT OF 50-60KT
MID LEVEL FLOW. AS THE LIKELIHOOD OF MORE SURFACE-BASED CONVECTION
BECOMES MORE EVIDENT AND POTENTIAL SEVERE WEATHER THREAT BECOMES
MORE WIDESPREAD...WATCHES WILL BE POSSIBLE.

..CARBIN.. 07/08/2009


ATTN...WFO...BIS...BYZ...GGW...

[Dave]

MESOSCALE DISCUSSION 1487
NWS STORM PREDICTION CENTER NORMAN OK
1224 PM CDT WED JUL 08 2009

AREAS AFFECTED...PARTS OF SERN AL / CNTRL-SRN GA / SAVANNAH RIVER
VALLEY

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 081724Z - 081830Z

POTENTIAL FOR ISOLD DMGG WIND GUSTS WILL INCREASE THE NEXT FEW HOURS
ACROSS PARTS OF AL/GA/SC.

WATER VAPOR IMAGERY AT 17Z SHOWS A SHORTWAVE TROUGH OVER PARTS OF
THE LOWER MS RIVER VALLEY MOVING ESEWD TOWARDS ALABAMA THIS
AFTERNOON...AND MID-LEVEL DRY AIR HAS NOSED NEWD FROM SWRN PARTS OF
AL NEWD TOWARDS THE SC UPSTATE IN ADVANCE OF THE TROUGH. A WEAK
SURFACE LOW IS INVOF ATL/MCN WITH A DIFFUSE STATIONARY BOUNDARY
EXTENDING EWD TOWARDS THE MOUTH OF THE SAVANNAH RIVER. SURFACE
STREAMLINE ANALYSIS DEPICTS CONVERGENCE NE OF SURFACE LOW OVER NERN
GA/WRN SC WHERE ONGOING TSTM CLUSTER IS LOCATED AS OF 1720Z.

12Z FFC RAOB SHOWED NEARLY SATURATED LOW LEVELS UP TO 700MB BENEATH
A DRY MID-LEVEL LAYER. FURTHER DIABATIC HEATING WILL CONTINUE TO
DESTABILIZE THE BOUNDARY LAYER AS LOW LEVEL LAPSE RATES STEEPEN.
DESPITE WEAK MEAN WLY FLOW FAVORING PULSE-LIKE TSTMS WITH A GENERAL
W-E MOTION...HIGH DCAPE VALUES IN EXCESS OF 1000 J/KG WILL LIKELY
SUPPORT ISOLD/INCREASING POTENTIAL FOR WET MICROBURSTS. AN EVENTUAL
TRANSITION INTO ONE OR MORE WEAKLY ORGANIZED MULTICELL CLUSTERS MAY
OCCUR AS COLD POOLS CONSOLIDATE.

..SMITH.. 07/08/2009


ATTN...WFO...CHS...CAE...GSP...FFC...TAE...BMX...MOB...

[Dave]

MESOSCALE DISCUSSION 1488
NWS STORM PREDICTION CENTER NORMAN OK
1236 PM CDT WED JUL 08 2009

AREAS AFFECTED...OK...TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 081736Z - 081900Z

DAYTIME MCS CONTINUES TO EVOLVE ACROSS OK AND...WHILE LATEST TRENDS
INDICATE A CONTRACTION TO THE OVERALL AREA OF TSTMS...THIS
CONSOLIDATION HAS RESULTED IN SLIGHTLY BETTER MESOSCALE ORGANIZATION
TO THE OVERALL SYSTEM BUT A DECREASE IN AREAL COVERAGE OF SEVERE
HAIL THREAT. UPDRAFTS HAVE DEVELOPED IN THE POST-OUTFLOW ENVIRONMENT
NEAR OKC...AND ADDITIONAL DEVELOPMENT APPEARS POSSIBLE AS OUTFLOW
BOUNDARIES COLLIDE SHORTLY NEAR NRN POTTAWATOMIE COUNTY. EARLIER
CELLS THAT DEVELOPED AHEAD OF THE SYSTEM QUICKLY WEAKENED OVER
CLEVELAND COUNTY INDICATING THAT THE ENVIRONMENT FARTHER SOUTH AND
WEST OF THE MCS OUTFLOW BOUNDARY REMAINS HOSTILE TO PERSISTENT DEEP
CONVENTION.

LIFT ALONG LEADING EDGE OF SYSTEM COLD POOL AND IN THE PRESENCE OF
OUTFLOW BOUNDARY INTERSECTIONS MAY CONTINUE TO BE SUFFICIENT FOR
STORM/UPDRAFT FORMATION. PRC PROFILER INDICATES LITTLE CHANGE IN
WARM ADVECTION REGIME ACROSS CNTRL OK OVER THE LAST FEW HOURS WITH
10-15KT LOW LEVEL SWLY FLOW TOPPED BY 25-30KT MID LEVEL NWLY FLOW.
RESULTING CLOUD-BEARING SHEAR SHOULD CONTINUE TO SUPPORT ISOLATED
ORGANIZED UPDRAFTS AND POSSIBLY MCS MAINTENENCE. HOWEVER...THIS
POTENTIAL WILL ALSO BE TEMPERED BY STRONG CAPPING INVERSION ACROSS
WRN/CNTRL SECTIONS OF OK.

IF CONVECTION PERSISTS AND A LARGE ENOUGH DEEP COLD POOL SPREADS
S/SEWD INTO AXIS OF STRONG DESTABILIZATION AND WEAKENING INHIBITION
ACROSS SRN/SERN OK AND NRN TX...IT IS POSSIBLE THAT THE THREAT OF
DAMAGING WINDS WOULD INCREASE AND A WATCH MAY BE NEEDED.
HOWEVER...UNTIL THIS SCENARIO BEGINS TO APPEAR MORE
LIKELY...MARGINALLY SEVERE HAIL SHOULD BE THE GREATEST HAZARD...IN
ADDITION TO LOCAL HEAVY RAINFALL.

..CARBIN.. 07/08/2009


ATTN...WFO...SHV...TSA...FWD...OUN...

[Dave]

PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1157 AM CDT WED JUL 08 2009

...SEVERE THUNDERSTORMS EXPECTED OVER PARTS OF THE NORTHERN PLAINS
LATER TODAY AND TONIGHT...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
DEVELOPMENT OF WIDESPREAD DAMAGING WINDS OVER PARTS OF THE NORTHERN
PLAINS LATER TODAY AND TONIGHT.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE

EASTERN MONTANA
SOUTHERN NORTH DAKOTA
NORTHERN SOUTH DAKOTA

ELSEWHERE...SEVERE STORMS ARE ALSO POSSIBLE FROM...A PORTION OF THE
CNTRL AND SRN PLAINS AND SERN STATES.

UPPER JET CURRENTLY MOVING THROUGH THE NRN ROCKIES WILL ADVANCE INTO
THE NRN PLAINS THIS EVENING ACCOMPANIED BY A COLD FRONT. THE
ATMOSPHERE IS EXPECTED TO BECOME MODERATELY UNSTABLE FROM ERN
MONTANA INTO THE DAKOTAS AS THE SURFACE LAYER CONTINUES TO WARM.
STORMS WILL LIKELY REDEVELOP OVER ERN MT AND WRN ND/NWRN SD LATER
TODAY ALONG AND AHEAD OF THE FRONT WITHIN ZONE OF INCREASING DEEP
LAYER FORCING FOR ASCENT IN ASSOCIATION WITH THE UPPER JET AND
STRENGTHENING SLY LOW LEVEL JET. VERTICAL SHEAR WILL INCREASE AS THE
UPPER JET APPROACHES...AND THE INITIAL STORMS WILL LIKELY DEVELOP
SUPERCELL STRUCTURES WITH LARGE HAIL LIKELY AND ISOLATED TORNADOES
POSSIBLE. HOWEVER...TREND SHOULD BE FOR STORMS TO EVOLVE INTO A
LARGE THUNDERSTORM COMPLEX AND CONTINUE EWD THROUGH THE DAKOTAS THIS
EVENING WITH A THREAT OF WIDESPREAD DAMAGING WIND.

STATE AND LOCAL EMERGENCY MANAGERS ARE MONITORING THIS DEVELOPING
SITUATION. THOSE IN THE THREATENED AREA ARE URGED TO REVIEW SEVERE
WEATHER SAFETY RULES AND TO LISTEN TO RADIO...TELEVISION...AND NOAA
WEATHER RADIO FOR POSSIBLE WATCHES...WARNINGS...AND STATEMENTS LATER
TODAY.

..DIAL.. 07/08/2009

[Dave]

PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1157 AM CDT WED JUL 08 2009

...SEVERE THUNDERSTORMS EXPECTED OVER PARTS OF THE NORTHERN PLAINS
LATER TODAY AND TONIGHT...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
DEVELOPMENT OF WIDESPREAD DAMAGING WINDS OVER PARTS OF THE NORTHERN
PLAINS LATER TODAY AND TONIGHT.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE

EASTERN MONTANA
SOUTHERN NORTH DAKOTA
NORTHERN SOUTH DAKOTA

ELSEWHERE...SEVERE STORMS ARE ALSO POSSIBLE FROM...A PORTION OF THE
CNTRL AND SRN PLAINS AND SERN STATES.

UPPER JET CURRENTLY MOVING THROUGH THE NRN ROCKIES WILL ADVANCE INTO
THE NRN PLAINS THIS EVENING ACCOMPANIED BY A COLD FRONT. THE
ATMOSPHERE IS EXPECTED TO BECOME MODERATELY UNSTABLE FROM ERN
MONTANA INTO THE DAKOTAS AS THE SURFACE LAYER CONTINUES TO WARM.
STORMS WILL LIKELY REDEVELOP OVER ERN MT AND WRN ND/NWRN SD LATER
TODAY ALONG AND AHEAD OF THE FRONT WITHIN ZONE OF INCREASING DEEP
LAYER FORCING FOR ASCENT IN ASSOCIATION WITH THE UPPER JET AND
STRENGTHENING SLY LOW LEVEL JET. VERTICAL SHEAR WILL INCREASE AS THE
UPPER JET APPROACHES...AND THE INITIAL STORMS WILL LIKELY DEVELOP
SUPERCELL STRUCTURES WITH LARGE HAIL LIKELY AND ISOLATED TORNADOES
POSSIBLE. HOWEVER...TREND SHOULD BE FOR STORMS TO EVOLVE INTO A
LARGE THUNDERSTORM COMPLEX AND CONTINUE EWD THROUGH THE DAKOTAS THIS
EVENING WITH A THREAT OF WIDESPREAD DAMAGING WIND.

STATE AND LOCAL EMERGENCY MANAGERS ARE MONITORING THIS DEVELOPING
SITUATION. THOSE IN THE THREATENED AREA ARE URGED TO REVIEW SEVERE
WEATHER SAFETY RULES AND TO LISTEN TO RADIO...TELEVISION...AND NOAA
WEATHER RADIO FOR POSSIBLE WATCHES...WARNINGS...AND STATEMENTS LATER
TODAY.

..DIAL.. 07/08/2009

[CrazyC83]

Looks like a derecho possible late this evening/overnight (maybe into tomorrow morning?) across the northern Plains. Tornado threat should be mostly west Dakotas before then, and embedded in the derecho.

[Dave]

I'm seeing the same thing Crazy. Timelines are taking it across the ND through the night with it going into the Grand Forks area anytime after 3 am cdt. Grand Forks NWS has a briefing which is showing the formation of a Low over the MT/WY area this afternoon, on radar I'm getting returns now out of Billings MT and larger cell working northwest of Minox ND.

Here's the multimedia briefing from the Grand Forks ND NWS office:

http://www.crh.noaa.gov/fgf/?n=webbriefing

The area I'm specifically watching is Larimore ND, west of Grand Forks - yes special friend & her kids live there in a mobile home. I'm staying up now until it's through them and into MN at least. Radar activity as of 3:47 pm edt is basically quiet in the MT, WY, SD, & ND regions. I'm sure that will change the further into the night we go. I have direct contact with her via cell & landline so we're covered there. Let's see what developes from here on out. (worried? me? yes for once).

Any info you or anyone can bring in please do.

Btw they tested the tornado warning sirens in Larimore at noon today cdt and are supposed to do it again tonight at 6 pm cdt...city and EMS officials are taking this serious as well.

[CrazyC83]

Awaiting the 2000Z update. High risk?

[Dave]

We're going to get a watch soon..



MESOSCALE DISCUSSION 1489
NWS STORM PREDICTION CENTER NORMAN OK
0202 PM CDT WED JUL 08 2009

AREAS AFFECTED...MT...ND...SD...WY

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 081902Z - 082030Z

AS ADVERTISED IN EARLIER OUTLOOKS AND EARLIER MESOSCALE
DISCUSSION...MORE WIDESPREAD AND DANGEROUS THUNDERSTORM DEVELOPMENT
APPEARS LIKELY ACROSS THE NRN HIGH PLAINS THIS AFTERNOON. THIS
DEVELOPMENT IS EXPECTED TO ENSUE WITHIN/BENEATH BELT OF STRONGLY
DIFFLUENT 60-100KT MID TO UPPER LEVEL FLOW. THESE POTENT LARGE-SCALE
KINEMATICS/DYNAMICS HAVE ALREADY RESULTED IN A VERY ORGANIZED AND
LONG-LIVED SUPERCELL THAT RACED NEWD ACROSS NERN MT THIS MORNING AND
WAS CROSSING INTO WRN ND AND WEAKENING ATTM.

IN THE WAKE OF THIS SLIGHTLY ELEVATED CELL...AIRMASS ACROSS MUCH OF
ERN MT AND ADJACENT AREAS OF ND/SD/WY HAS BECOME MORE UNSTABLE AND
UNCAPPED WITH DAYTIME HEATING. THIS DESTABILIZATION SHOULD
CONTRIBUTE TO RAPID AND ROBUST TSTM DEVELOPMENT WITHIN SURFACE
TROUGH AND AHEAD OF THE COLD FRONT NOW MOVING INTO THESE AREAS FROM
THE WEST. GIVEN DEEP-LAYER EFFECTIVE SHEAR ON THE ORDER OF
50KT...DISCRETE CELLS SHOULD QUICKLY ACQUIRE SUPERCELL STRUCTURE AND
POSE A THREAT OF LARGE HAIL. TORNADO POTENTIAL MAY EVOLVE WITH A
COUPLE OF THE MORE PERSISTENT UPDRAFTS NEAR THE LEE TROUGH AND
TRACKING PREFERENTIALLY ALONG OUTFLOW/FRONTAL AND DIFFERENTIAL
HEATING BOUNDARIES SITUATED ACROSS THE AREA. UPSCALE ORGANIZATION
ENHANCED BY THE APPROACH OF THE UPPER TROUGH AND SURFACE DEVELOPMENT
SHOULD...EVENTUALLY...AID IN LINEAR MCS DEVELOPMENT WITH WIDESPREAD
DAMAGING WIND POTENTIAL SPREADING EAST ACROSS THE DAKOTAS LATER
TODAY/TONIGHT.

..CARBIN.. 07/08/2009


ATTN...WFO...BIS...UNR...BYZ...GGW...

[Dave]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0306 PM CDT WED JUL 08 2009

VALID 082000Z - 091200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER FAR SERN MT...SRN ND AND
NRN/CNTRL SD...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE NRN/CNTRL
PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF SERN OK/NERN
TX...

...ERN MT/NERN WY ACROSS THE NRN PLAINS...
PREVIOUS FORECAST ON TRACK WITH LITTLE CHANGE NEEDED ATTM. ADJUSTED
WRN EXTENT OF SLGT RISK TO MATCH CURRENT POSITION OF COLD
FRONT/SURFACE LOW OVER ERN MT. REFER TO MCD 1489 FOR ADDITIONAL
SHORT-TERM INFORMATION.

...CNTRL/SRN PLAINS...
REMNANT LONG-LIVED TSTM CLUSTERS PERSIST OVER CNTRL OK AND E-CNTRL
KS. MODEL FORECASTS HAVE STRUGGLED WITH THE HANDLING OF THESE
CONVECTIVE AREAS AND LENDS TO UNCERTAINTY WITH REGARD TO THE
EVOLUTION OF THIS ACTIVITY THROUGH TONIGHT. NEVERTHELESS...WITH
INHIBITION WEAKENING AND DEEP-LAYER SHEAR SUFFICIENT FOR CONTINUED
UPDRAFT ORGANIZATION...THREAT FOR ISOLATED DAMAGING WINDS AND
MARGINAL SEVERE HAIL SHOULD CONTINUE. IN THE WAKE OF THIS
ACTIVITY...ADDITIONAL CONVECTIVE DEVELOPMENT SHOULD BE LARGELY
SUPPRESSED ACROSS CNTRL KS/NRN OK BY LACK OF CONVERGENCE AND STOUT
INHIBITION AS MID-LEVEL HEIGHTS RISE DOWNSTREAM OF VIGOROUS NRN
ROCKIES SHORT WAVE TROUGH. REFER TO MCD 1490 FOR ADDITIONAL
SHORT-TERM INFORMATION ON THE ERN KS CLUSTER.

...SOUTHEAST...
ONGOING PULSE TO LOOSELY ORGANIZED MULTICELL TSTMS MAY STILL POSE A
THREAT FOR ISOLATED WET MICROBURSTS INTO EARLY EVENING. VERY MOIST
THERMODYNAMIC PROFILES /WITH GPS PW VALUES AROUND 2 INCHES/ AND WEAK
LOW-LEVEL FLOW /PER AREA VWP DATA/ HAVE LIMITED POTENTIAL FOR A MORE
ORGANIZED THREAT. THUS...A SLGT RISK NO LONGER APPEARS WARRANTED.

...SRN NEW ENGLAND...
RELATIVELY COLD TEMPERATURES /-16 TO -18C AT 500 MB/ AND FAST WLY
FLOW IN THE MID-LEVELS WILL CONTINUE TO SUPPORT A FEW BRIEFLY
ORGANIZED UPDRAFTS WHERE SURFACE TEMPERATURES HAVE WARMED INTO THE
LOWER TO MIDDLE 70S. WITH ANEMIC LOWER-LEVEL FLOW /PER AREA VWP
DATA/...PRIMARY THREAT SHOULD BE MARGINAL SEVERE HAIL INTO EARLY
EVENING.

..GRAMS/DIAL.. 07/08/2009

.PREV DISCUSSION... /ISSUED 1134 AM CDT WED JUL 08 2009/

...ERN MT/NERN WY ACROSS THE NRN PLAINS...

WIDESPREAD SEVERE THUNDERSTORM EPISODE EXPECTED LATE THIS AFTERNOON
AND TONIGHT...

UPPER SHORT WAVE TROUGH NOW EVIDENT IN WATER VAPOR IMAGERY OVER ERN
PARTS OF WA AND OREGON IS FORECAST TO MOVE ENEWD ACROSS MT AND INTO
WRN ND BY THE END OF THE PERIOD. A STRONG MID/UPPER LEVEL JET
STREAK OVER THE NRN GREAT BASIN/INTERMOUNTAIN REGION IS EXPECTED TO
TRANSLATE ENEWD ACROSS THE NRN ROCKIES THIS AFTERNOON AND INTO THE
NRN HIGH PLAINS TONIGHT. AS THE UPPER LEVEL JET PROGRESSES
ENEWD...AN INTENSIFYING SOUTHERLY LOW LEVEL JET WILL DEVELOP LATE
THIS AFTERNOON INTO TONIGHT OVER THE CENTRAL/NRN PLAINS.

A SURFACE COLD FRONT CURRENTLY EXTENDS FROM ERN MT SWD INTO A LOW
OVER NERN WY...CONTINUING SWWD INTO NRN UT. THE LOW AND COLD FRONT
WILL MOVE SLOWLY EWD LATER THIS AFTERNOON AND EVENING TOWARD THE WRN
DAKOTAS BORDER...THEN ACCELERATING SOMEWHAT INTO THE ERN DAKOTAS BY
THE END OF THE PERIOD. LOW LEVEL CONVERGENCE NEAR THE LOW AND FRONT
IS EXPECTED TO PROVIDE THE PRIMARY FOCUS FOR SEVERE STORMS LATER
THIS AFTERNOON AND TONIGHT.

IN RESPONSE TO THE DEVELOPING LOW LEVEL JET...MOISTURE IS LIKELY TO
BE TRANSPORTED NWD IN ADVANCE OF THE COLD FRONT WITH SURFACE DEW
POINTS IN THE LOW/MID 60S EXPECTED THIS AFTERNOON. PLUME OF STEEP
MID LEVEL LAPSE RATES EVIDENT IN THE RAP AND RIW SOUNDINGS IS
EXPECTED TO SPREAD EWD ACROSS PARTS OF THE NRN PLAINS...AND WHEN
COUPLED WITH INCREASING MOISTURE AND STRONG DIABATIC HEATING FROM
SERN MT INTO THE DAKOTAS WILL RESULT IN MODERATE INSTABILITY WITH
MLCAPE FROM 1500-2500 J/KG.

ISOLATED STRONG ELEVATED THUNDERSTORMS ARE OCCURRING THIS MORNING
OVER NERN MT AND EXTREME WRN ND. THESE STORMS WILL BE MONITORED AS
THEY PROGRESS EWD THROUGH THE LATE MORNING HOURS AS THEY HAVE
POTENTIAL TO PRODUCE HAIL AND POSSIBLE STRONG WIND GUSTS. PRIMARY
SEVERE THREAT IS EXPECTED TO DEVELOP LATER THIS AFTERNOON AND
EVENING...WITH INITIAL DISCRETE CELLS DEVELOPING OVER PARTS OF SOUTH
CENTRAL/ERN MT AND NERN WY. THESE STORMS WILL BE ON THE NOSE OF THE
UPPER LEVEL JET...AND WITHIN AN ENVIRONMENT CHARACTERIZED BY 35-45
KT OF DEEP LAYER SHEAR THAT WILL BE SUPPORTIVE OF SUPERCELLS. THESE
WILL BE CAPABLE OF LARGE HAIL...DAMAGING WIND GUSTS AND A FEW
TORNADOES. THUNDERSTORMS ARE EXPECTED TO GRADUALLY SPREAD EWD INTO
THE WRN DAKOTAS THIS EVENING...WITH ACTIVITY LIKELY GROWING UPSCALE
INTO A FORWARD PROPAGATING MCS WITH EMBEDDED BOW ECHO STRUCTURES.
ALTHOUGH POTENTIAL FOR LARGE HAIL AND ISOLATED TORNADOES WILL
CONTINUE...THE PRIMARY SEVERE WEATHER THREAT IS EXPECTED TO
TRANSITION TO WIDESPREAD DAMAGING WIND GUSTS AS THE BOW ECHO SYSTEM
MOVES EWD ACROSS PARTS OF THE DAKOTAS.

...CENTRAL/SRN PLAINS...
ELEVATED STRONG THUNDERSTORMS CONTINUE TO MOVE SSEWD ACROSS SERN NEB
AND PARTS OF NRN/ERN OK WITHIN BAND OF STRONGER NWLY FLOW ALOFT.
RADAR ANALYSIS INDICATES THAT UPDRAFT CORES HAVE BEEN PULSING TO
SOME EXTENT. HOWEVER...OVERALL PERSISTENCE OF CONVECTION INTO THE
LATE MORNING SUGGESTS THAT STORMS HAVE POTENTIAL TO BECOME
SURFACE-BASED THIS AFTERNOON. HAIL AND POSSIBLY STRONG WIND GUSTS
WILL BE POSSIBLE WITH THE STORMS.

ADDITIONAL CONVECTION IS EXPECTED TO DEVELOP ALONG THE LEE TROUGH
OVER THE HIGH PLAINS OF NEB AND POSSIBLY NWRN KS LATE THIS AFTERNOON
AND EVENING...AND WOULD MOVE SEWD ACROSS PARTS OF THE CENTRAL PLAINS
INTO THE OVERNIGHT HOURS. LARGE HAIL AND DAMAGING WIND WILL BE
POSSIBLE WITH STRONGER CELLS GIVEN ENVIRONMENT CHARACTERIZED BY
MLCAPE OF 1500-2000 J/KG AND DEEP LAYER SHEAR OF 40-45 KT.

...SERN STATES...
A BAND OF STRONG STORMS IS OCCURRING OVER THE NRN GULF OF MEXICO AND
EWD INTO NRN FL. NORTH OF THIS ACTIVITY...STORMS ARE LIKELY TO
REDEVELOP WITHIN VERY MOIST AIR MASS FROM PARTS OF AL EWD INTO GA
AND SC. STORM INTENSITY WILL BE ENHANCED BY DYNAMIC FORCING IN
ADVANCE OF A SHORT WAVE TROUGH MOVING EWD FROM THE LOWER MS VALLEY.
THERE IS SUFFICIENT WESTERLY FLOW ALOFT AND VERTICAL SHEAR TO AID IN
STORM ORGANIZATION...WITH STRONGER CELLS CAPABLE OF PRODUCING WET
MICROBURSTS AND POSSIBLY HAIL.

[Dave]

They're holding at a moderate risk still. Here's wind, hail, & tornado numbers though.

[Dave]

Here's the counties for Tornado Watch # 563, will get full update as soon as it's loaded to the server.

BULLETIN - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH OUTLINE UPDATE FOR WT 563
NWS STORM PREDICTION CENTER NORMAN OK
220 PM MDT WED JUL 8 2009

TORNADO WATCH 563 IS IN EFFECT UNTIL 1000 PM MDT FOR THE
FOLLOWING LOCATIONS

MTC011-017-021-025-075-079-083-109-090400-
/O.NEW.KWNS.TO.A.0563.090708T2020Z-090709T0400Z/

MT
. MONTANA COUNTIES INCLUDED ARE

CARTER CUSTER DAWSON
FALLON POWDER RIVER PRAIRIE
RICHLAND WIBAUX


NDC001-007-011-025-033-037-041-049-053-055-057-059-061-065-075-
085-087-089-101-105-090400-
/O.NEW.KWNS.TO.A.0563.090708T2020Z-090709T0400Z/

ND
. NORTH DAKOTA COUNTIES INCLUDED ARE

ADAMS BILLINGS BOWMAN
DUNN GOLDEN VALLEY GRANT
HETTINGER MCHENRY MCKENZIE
MCLEAN MERCER MORTON
MOUNTRAIL OLIVER RENVILLE
SIOUX SLOPE STARK
WARD WILLIAMS


SDC019-031-033-041-055-063-081-093-103-105-137-090400-
/O.NEW.KWNS.TO.A.0563.090708T2020Z-090709T0400Z/

SD
. SOUTH DAKOTA COUNTIES INCLUDED ARE

BUTTE CORSON CUSTER
DEWEY HAAKON HARDING
LAWRENCE MEADE PENNINGTON
PERKINS ZIEBACH


WYC005-011-045-090400-
/O.NEW.KWNS.TO.A.0563.090708T2020Z-090709T0400Z/

WY
. WYOMING COUNTIES INCLUDED ARE

CAMPBELL CROOK WESTON


ATTN...WFO...BYZ...UNR...ABR...BIS...GGW...

[Dave]

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 563
NWS STORM PREDICTION CENTER NORMAN OK
220 PM MDT WED JUL 8 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

EXTREME EASTERN MONTANA
WESTERN NORTH DAKOTA
WESTERN SOUTH DAKOTA
NORTHEAST WYOMING

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 220 PM UNTIL
1000 PM MDT.

TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 100 STATUTE
MILES EAST AND WEST OF A LINE FROM 55 MILES EAST NORTHEAST OF
WILLISTON NORTH DAKOTA TO 35 MILES SOUTH SOUTHWEST OF RAPID CITY
SOUTH DAKOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

DISCUSSION...THUNDERSTORMS ARE EXPECTED TO DEVELOP AND INTENSIFY
ALONG FRONTAL BOUNDARY OVER EXTREME ERN MT AND NERN WY DURING THE
NEXT 1-2 HRS. AIR MASS HAS DESTABILIZED THIS AFTERNOON WITH MLCAPE
OF 1000-1500 J/KG AS STRONG HEATING TAKES PLACE SOUTH OF EARLIER
CONVECTION OVER NERN MT AND NWRN ND. DYNAMIC FORCING FOR LARGE
SCALE ASCENT WILL INCREASE THROUGH THE EVENING HAS A SHORT WAVE
TROUGH PROGRESSES ENEWD ACROSS MT...IN CONJUNCTION WITH A VERY
STRONG MID/UPPER LEVEL JET STREAK. THIS IS CONTRIBUTING TO 40-50 KT
DEEP LAYER SHEAR SUPPORTIVE OF SUPERCELLS...WHILE STRENGTHENING LOW
LEVEL JET AND VEERING PROFILES IN LOWEST 2-3 KM INDICATE POTENTIAL
FOR A FEW TORNADOES WITH INITIAL STORM DEVELOPMENT. STORMS ARE
EXPECTED TO GROW UPSCALE BY THE EVENING HOURS WITH A
FORWARD-PROPAGATING LINEAR MCS MOVING ACROSS WRN ND AND PARTS OF WRN
SD AND INCREASING THREAT FOR MORE WIDESPREAD WIND DAMAGE.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 26035.


...WEISS

[Dave]

MESOSCALE DISCUSSION 1490
NWS STORM PREDICTION CENTER NORMAN OK
0259 PM CDT WED JUL 08 2009

AREAS AFFECTED...PARTS OF NERN-ERN KS

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 081959Z - 082100Z

TRENDS WILL BE MONITORED OVER THE NEXT FEW HOURS FOR ADDITIONAL
CONVECTIVE DEVELOPMENT OVER PARTS OF NERN KS. ONGOING INTENSE TSTM
OVER FRANKLIN COUNTY KS WILL LIKELY PERSIST AND MOVE SSEWD INTO
PARTS OF FAR ERN/SERN KS.

RECENT KTWX RADAR IMAGERY HAS SHOWN INITIALLY SLIGHTLY ELEVATED TSTM
OVER NERN KS HAS INTENSIFIED AND HAS LIKELY BECOME SURFACE-BASED IN
THE PAST HOUR OR SO. THIS IS PROBABLY DUE IN PART TO IT
ENCOUNTERING A DESTABILIZING BOUNDARY LAYER IN ADDITION TO MID-UPPER
SUPPORT FOR UPWARD VERTICAL MOTION AHEAD OF A WEAK IMPULSE OVER THE
LOWER MO RIVER VALLEY CRESTING LARGER SCALE UPPER RIDGE. VISIBLE
SATELLITE IMAGERY/SURFACE ANALYSIS SHOW A MODEST CU FIELD HAS
DEVELOPED ALONG AND TO THE W OF TRAILING OUTFLOW BOUNDARY OVER NERN
KS. MODIFIED 12Z TOP RAOB AND 18Z AREA RUC SOUNDINGS SUGGEST LITTLE
CINH REMAINS. HOWEVER...BOTH ETAKF/RUC FORECAST SOUNDINGS DEPICT A
WARM LAYER IN THE H75-H7 LAYER...INDICATIVE OF A WEAKENED BUT
REMAINING CAPPING INVERSION. AS A RESULT...THERE IS UNCERTAINTY
WHETHER OR NOT ADDITIONAL STORMS CAN INITIATE OVER THE AREA THIS
AFTERNOON THAT IS CHARACTERIZED AS MODERATE-STRONGLY UNSTABLE AND
WITHIN BELT OF STRONG NWLY FLOW ALOFT. IF STORMS DO INDEED
DEVELOP...AN ORGANIZED SEVERE THREAT MAY EVOLVE ALONG INSTABILITY
GRADIENT OVER ERN KS.

..SMITH.. 07/08/2009


ATTN...WFO...SGF...EAX...TOP...ICT...

[Dave]

TORNADO WATCH PROBABILITIES FOR WT 0563
NWS STORM PREDICTION CENTER NORMAN OK
0328 PM CDT WED JUL 08 2009

WT 0563
PROBABILITY TABLE:
PROB OF 2 OR MORE TORNADOES : 40%
PROB OF 1 OR MORE STRONG /F2-F5/ TORNADOES : 20%
PROB OF 10 OR MORE SEVERE WIND EVENTS : 80%
PROB OF 1 OR MORE WIND EVENTS >= 65 KNOTS : 40%
PROB OF 10 OR MORE SEVERE HAIL EVENTS : 40%
PROB OF 1 OR MORE HAIL EVENTS >= 2 INCHES : 30%
PROB OF 6 OR MORE COMBINED SEVERE HAIL/WIND EVENTS : 90%

&&
ATTRIBUTE TABLE:
MAX HAIL /INCHES/ : 3.0
MAX WIND GUSTS SURFACE /KNOTS/ : 70
MAX TOPS /X 100 FEET/ : 500
MEAN STORM MOTION VECTOR /DEGREES AND KNOTS/ : 26035
PARTICULARLY DANGEROUS SITUATION : NO