Severe weather outbreak: June 17 - 19

[CrazyC83]

SEL3

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 463
NWS STORM PREDICTION CENTER NORMAN OK
1150 AM EDT THU JUN 18 2009

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

MUCH OF THE FLORIDA PENINSULA

EFFECTIVE THIS THURSDAY MORNING AND EVENING FROM 1150 AM UNTIL
700 PM EDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 70
STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES WEST
NORTHWEST OF JACKSONVILLE FLORIDA TO 25 MILES SOUTHEAST OF NAPLES
FLORIDA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 459...WW 460...WW
461...WW 462...

DISCUSSION...THUNDERSTORMS WILL INCREASE IN NUMBER AND INTENSITY
THRU THE AFTERNOON AS THE AIR MASS MDTLY UNSTABLE WITH STEEP MID
LEVEL LAPSE RATES. SEVERE THUNDERSTORMS EXPECTED...PARTICULARLY
ASSOCIATED WITH LOW LEVEL CONVERGENCE ALONG SEA BREEZE FRONTS AS
THEY MOVE INLAND.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM
MOTION VECTOR 36015.


...HALES

[Bunkertor]

Poll !

The 1630 will be

- in time
- 10 min delayed
> 10 min delayed
- issued prior to the scheduled time

I'm guessing it might be early, since a lot of decisions have already been made. The only big question mark is whether the Midwest goes up to a high risk.

OK, this would require an extra poll. I bet it will be delayed up to 10 min.

[RL3AO]

Might be an interesting afternoon for me. Looks like our severe weather season is starting with a bang.

[brunota2003]

I'll say in time

[Bunkertor]

Poll !

The 1630 will be

- in time |
- 10 min delayed |
> 10 min delayed
- issued prior to the scheduled time |

I wonder what the guys will say ´bout the heat watch area

[Bunkertor]

I just popped in over there. Check this out:

severestudios

TORNADO EMERGENCY FOR AURORA, NE. Large tornado moving NE Hwy 34 toward Aurora! Take cover now! Streaming it live on 3 cams! (6/17 9:16)6 minutes ago from TweetDeck

Aurora Tornado

http://www.spiegel.de/video/video-1008107.html

[Bunkertor]

OK, >10 minutes FTW. We all sucked

[CrazyC83]

SPC AC 181630

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT THU JUN 18 2009

VALID 181630Z - 191200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF FAR ERN SD...SRN
MN...MUCH OF IA...SRN WI...NRN IL...AND NRN IN...

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OS SERN KY...ERN
TN...WRN NC...NERN GA AND WRN SC...

...THERE IS A SLGT RISK OF SVR TSTMS STRETCHING FROM THE NRN/CENTRAL
PLAINS EWD TO THE MID ATLANTIC STATES AND SEWD TO FL...

WIDESPREAD SEVERE WEATHER IS EXPECTED THROUGH TONIGHT ACROSS A LARGE
PORTION OF THE COUNTRY FROM THE NRN/CENTRAL PLAINS SEWD INTO THE MID
ATLANTIC AND SOUTHEASTERN STATES.

...ERN TN VALLEY SEWD INTO THE SERN STATES...
A MATURE FORWARD PROPAGATING BOW ECHO WAS MOVING SEWD AT 50 KT INTO
SERN KY AT MID MORNING...REFERENCE WW 461. THE COMBINATION OF A WELL
MIXED ELEVATED LAYER/STEEP MID LEVEL LAPSE RATES AND A VERY MOIST
BOUNDARY LAYER WILL RESULT IN MLCAPES BETWEEN 3000-4000 J/KG THIS
AFTERNOON. ALTHOUGH DEEP LAYER SHEAR IS ONLY AROUND 30-35 KT...THE
DEGREE OF INSTABILITY AND STRONG HEATING IS LIKELY TO MAINTAIN THIS
SYSTEM THROUGH THE DAY...WITH WIDESPREAD WIND DAMAGE LIKELY. A
MODERATE RISK HAS BEEN ADDED HIGHLIGHTING THE ENHANCED WIND THREAT.
THE CIRCULATION AROUND THE UPPER HIGH...CENTERED IN LA...IS EXPECTED
TO CARRY THIS MCS SEWD TOWARD THE SERN GA/SC COAST THIS EVENING.

...SRN MO RIVER AND OH VALLEYS...
A SMALL SEVERE MCS IS CURRENTLY MOVING THROUGH ERN IA...REFERENCE WW
462. THOUGH THIS SYSTEM WILL BE MOVING THROUGH AN AIR MASS
CONTAMINATED BY OVERNIGHT CONVECTION...A LARGE RESERVOIR OF HIGH
INSTABILITY RESIDES TO THE SOUTH AND SOUTHWEST OF IT ACROSS THE
CENTRAL PLAINS AND MID MS VALLEY. WITH HEATING...BY MID AFTERNOON
MLCAPES FROM 3000-5000 J/KG WILL EXTEND FROM NEB/SD EWD INTO THE WRN
GREAT LAKES. OTHER ROUNDS OF SEVERE STORMS ARE LIKELY TO DEVELOP
THIS AFTERNOON ALONG OUTFLOW BOUNDARIES FROM OVERNIGHT/ MORNING
CONVECTION AND WEAK COLD FRONT/TROUGH LOCATED ACROSS THE CENTRAL
PLAINS. ONCE STORMS DEVELOP...THE EXTREME INSTABILITY AND 50-60 KT
DEEP LAYER SHEAR WILL SUPPORT INTENSE SUPERCELLS FORMING OVER
PORTIONS OF IA/NEB/SD/SRN MN AREA THIS AFTERNOON. VERY LARGE HAIL IN
EXCESS OF 3 INCHES...DAMAGING WINDS...AND TORNADOES/SOME
SIGNIFICANT/ ARE EXPECTED WITH THESE STORMS. THIS EVENING...THE
STORMS ARE LIKELY TO CONSOLIDATE INTO A LARGE MCS/BOW ECHO WITH A
RISK FOR WIDESPREAD DAMAGING WINDS ACROSS THE ERN HALF OF THE
MODERATE RISK OVER PARTS OF SRN WI/NRN IL AND NWRN INDIANA.

...MID ATLANTIC REGION...
THOUGH DIFFICULT TO SEE ON SATELLITE IMAGERY ATTM...MODELS SUGGEST A
SHORTWAVE TROUGH WILL SHIFT SEWD INTO THE REGION THIS AFTERNOON.
EVEN THOUGH CLOUDS HAVE BEEN SLOW TO CLEAR EAST OF THE
MOUNTAINS...DUE TO DEEP MOISTURE AS INDICATED ON MORNING SOUNDINGS
...WEAK CONVECTION HAD ALREADY DEVELOPED OVER THE SUNNIER AREAS NEAR
THE HIGHER TERRAIN. WLY WINDS FROM 850 TO 500 MB SHOULD AID IN SOME
MID LEVEL LAYER DRYING THROUGH THE DAY. GIVEN THE MOIST BOUNDARY
LAYER AND HEATING...THIS SHOULD PROVIDE A MODERATELY UNSTABLE AIR
MASS. SPEED SHEAR APPEARS SUFFICIENT FOR SUPERCELLS WITH
HAIL/DAMAGING WINDS THE PRIMARY THREATS. HOWEVER... ISALLOBARICALLY
BACKED SURFACE WINDS INVOF WARM FRONT IN DELMARVA SUGGESTS ALSO THE
POTENTIAL FOR A TORNADO OR TWO.

...WRN TX NEWD INTO CENTRAL KS...
SIMILAR TO YESTERDAY...MID/HIGH LEVEL TROPICAL MOISTURE CONTINUES TO
STREAM NWD FROM MEXICO INTO WRN KS. MORNING AMA/DDC SOUNDINGS
INDICATE MID 90 TEMPERATURES SHOULD PROVIDE SUFFICIENT LIFT TO BREAK
CAPPING INVERSION ALONG ERN EDGE OF THICKER CLOUDS. MODERATE
INSTABILITY...35-45 TEMPERATURE/DEWPOINT SPREADS AND 30-40 KT MID
LEVEL WINDS WILL BE FAVORABLE FOR RELATIVELY HIGH BASED STORMS TO
PRODUCE WIND DAMAGE AS THEY SPREAD NEWD LATER THIS AFTERNOON AND
EVENING.

...FL PENINSULA...
VSBY IMAGERY INDICATED AN MCV WAS LOCATED ABOUT 20N JAX AND STORMS
WERE LOCATED AHEAD OF IT WEST OF JAX. THIS SYSTEM IS EMBEDDED WITH
20-25 KT NLY WINDS ALOFT AND SHOULD TRACK SWWD THROUGH THE
AFTERNOON. STRONG INSTABILITY AND RELATIVELY STRONG MID LEVEL WINDS
WILL BE SUFFICIENT FOR SEVERE HAIL AND WIND DAMAGE...REFERENCE WW
463.

..IMY/GARNER.. 06/18/2009

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
CURRENT UTC TIME: 1642Z (12:42PM), RELOAD THIS PAGE TO UPDATE THE TIME

[CrazyC83]

The new moderate risk (beneath the PDS watch) isn't even hatched (just 45 wind). Makes little sense, but I guess the forecasters see things differently?

[Siberian Express]

Anybody else notice, no discussion about the upper Mississippi valley mod risk in this discussion?

SPC AC 181630

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT THU JUN 18 2009

VALID 181630Z - 191200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF FAR ERN SD...SRN
MN...MUCH OF IA...SRN WI...NRN IL...AND NRN IN...

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OS SERN KY...ERN
TN...WRN NC...NERN GA AND WRN SC...

...THERE IS A SLGT RISK OF SVR TSTMS STRETCHING FROM THE NRN/CENTRAL
PLAINS EWD TO THE MID ATLANTIC STATES AND SEWD TO FL...

WIDESPREAD SEVERE WEATHER IS EXPECTED THROUGH TONIGHT ACROSS A LARGE
PORTION OF THE COUNTRY FROM THE NRN/CENTRAL PLAINS SEWD INTO THE MID
ATLANTIC AND SOUTHEASTERN STATES.

...ERN TN VALLEY SEWD INTO THE SERN STATES...
A MATURE FORWARD PROPAGATING BOW ECHO WAS MOVING SEWD AT 50 KT INTO
SERN KY AT MID MORNING...REFERENCE WW 461. THE COMBINATION OF A WELL
MIXED ELEVATED LAYER/STEEP MID LEVEL LAPSE RATES AND A VERY MOIST
BOUNDARY LAYER WILL RESULT IN MLCAPES BETWEEN 3000-4000 J/KG THIS
AFTERNOON. ALTHOUGH DEEP LAYER SHEAR IS ONLY AROUND 30-35 KT...THE
DEGREE OF INSTABILITY AND STRONG HEATING IS LIKELY TO MAINTAIN THIS
SYSTEM THROUGH THE DAY...WITH WIDESPREAD WIND DAMAGE LIKELY. A
MODERATE RISK HAS BEEN ADDED HIGHLIGHTING THE ENHANCED WIND THREAT.
THE CIRCULATION AROUND THE UPPER HIGH...CENTERED IN LA...IS EXPECTED
TO CARRY THIS MCS SEWD TOWARD THE SERN GA/SC COAST THIS EVENING.

...SRN MO RIVER AND OH VALLEYS...
A SMALL SEVERE MCS IS CURRENTLY MOVING THROUGH ERN IA...REFERENCE WW
462. THOUGH THIS SYSTEM WILL BE MOVING THROUGH AN AIR MASS
CONTAMINATED BY OVERNIGHT CONVECTION...A LARGE RESERVOIR OF HIGH
INSTABILITY RESIDES TO THE SOUTH AND SOUTHWEST OF IT ACROSS THE
CENTRAL PLAINS AND MID MS VALLEY. WITH HEATING...BY MID AFTERNOON
MLCAPES FROM 3000-5000 J/KG WILL EXTEND FROM NEB/SD EWD INTO THE WRN
GREAT LAKES. OTHER ROUNDS OF SEVERE STORMS ARE LIKELY TO DEVELOP
THIS AFTERNOON ALONG OUTFLOW BOUNDARIES FROM OVERNIGHT/ MORNING
CONVECTION AND WEAK COLD FRONT/TROUGH LOCATED ACROSS THE CENTRAL
PLAINS. ONCE STORMS DEVELOP...THE EXTREME INSTABILITY AND 50-60 KT
DEEP LAYER SHEAR WILL SUPPORT INTENSE SUPERCELLS FORMING OVER
PORTIONS OF IA/NEB/SD/SRN MN AREA THIS AFTERNOON. VERY LARGE HAIL IN
EXCESS OF 3 INCHES...DAMAGING WINDS...AND TORNADOES/SOME
SIGNIFICANT/ ARE EXPECTED WITH THESE STORMS. THIS EVENING...THE
STORMS ARE LIKELY TO CONSOLIDATE INTO A LARGE MCS/BOW ECHO WITH A
RISK FOR WIDESPREAD DAMAGING WINDS ACROSS THE ERN HALF OF THE
MODERATE RISK OVER PARTS OF SRN WI/NRN IL AND NWRN INDIANA.

...MID ATLANTIC REGION...
THOUGH DIFFICULT TO SEE ON SATELLITE IMAGERY ATTM...MODELS SUGGEST A
SHORTWAVE TROUGH WILL SHIFT SEWD INTO THE REGION THIS AFTERNOON.
EVEN THOUGH CLOUDS HAVE BEEN SLOW TO CLEAR EAST OF THE
MOUNTAINS...DUE TO DEEP MOISTURE AS INDICATED ON MORNING SOUNDINGS
...WEAK CONVECTION HAD ALREADY DEVELOPED OVER THE SUNNIER AREAS NEAR
THE HIGHER TERRAIN. WLY WINDS FROM 850 TO 500 MB SHOULD AID IN SOME
MID LEVEL LAYER DRYING THROUGH THE DAY. GIVEN THE MOIST BOUNDARY
LAYER AND HEATING...THIS SHOULD PROVIDE A MODERATELY UNSTABLE AIR
MASS. SPEED SHEAR APPEARS SUFFICIENT FOR SUPERCELLS WITH
HAIL/DAMAGING WINDS THE PRIMARY THREATS. HOWEVER... ISALLOBARICALLY
BACKED SURFACE WINDS INVOF WARM FRONT IN DELMARVA SUGGESTS ALSO THE
POTENTIAL FOR A TORNADO OR TWO.

...WRN TX NEWD INTO CENTRAL KS...
SIMILAR TO YESTERDAY...MID/HIGH LEVEL TROPICAL MOISTURE CONTINUES TO
STREAM NWD FROM MEXICO INTO WRN KS. MORNING AMA/DDC SOUNDINGS
INDICATE MID 90 TEMPERATURES SHOULD PROVIDE SUFFICIENT LIFT TO BREAK
CAPPING INVERSION ALONG ERN EDGE OF THICKER CLOUDS. MODERATE
INSTABILITY...35-45 TEMPERATURE/DEWPOINT SPREADS AND 30-40 KT MID
LEVEL WINDS WILL BE FAVORABLE FOR RELATIVELY HIGH BASED STORMS TO
PRODUCE WIND DAMAGE AS THEY SPREAD NEWD LATER THIS AFTERNOON AND
EVENING.

...FL PENINSULA...
VSBY IMAGERY INDICATED AN MCV WAS LOCATED ABOUT 20N JAX AND STORMS
WERE LOCATED AHEAD OF IT WEST OF JAX. THIS SYSTEM IS EMBEDDED WITH
20-25 KT NLY WINDS ALOFT AND SHOULD TRACK SWWD THROUGH THE
AFTERNOON. STRONG INSTABILITY AND RELATIVELY STRONG MID LEVEL WINDS
WILL BE SUFFICIENT FOR SEVERE HAIL AND WIND DAMAGE...REFERENCE WW
463.

..IMY/GARNER.. 06/18/2009

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
CURRENT UTC TIME: 1642Z (12:42PM), RELOAD THIS PAGE TO UPDATE THE TIME

[RL3AO]

Yep, I noticed.

[Dave]

KIND & TIDS Indianapolis IN radar back in operation.

[Dave]

MESOSCALE DISCUSSION 1206
NWS STORM PREDICTION CENTER NORMAN OK
1252 PM CDT THU JUN 18 2009

AREAS AFFECTED...SERN ND / NERN SD / W-CNTRL MN

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 181752Z - 181915Z

THE THREAT FOR A FEW SEVERE STORMS IS EXPECTED TO INCREASE THIS
AFTERNOON AND CONVECTIVE TRENDS ARE BEING MONITORED FOR A POSSIBLE
WW.

A RATHER COMPLEX SURFACE PATTERN HAS EVOLVED TODAY OWING TO THE
PRESENCE OF MULTIPLE BOUNDARIES REMNANT FROM NOCTURNAL TSTM
ACTIVITY. BUT...IT APPEARS THAT SYNOPTIC SURFACE LOW WAS LOCATED
OVER N-CNTRL SD AS OF 17Z WITH ATTENDANT WARM FRONT EXTENDING
GENERALLY EWD INTO W-CNTRL MN /N OF A ABR-ATY-AXN LINE/. BASED ON
CURRENT SURFACE OBSERVATIONS AND 12Z MODEL GUIDANCE...THE AXIS OF
RICHER BOUNDARY LAYER MOISTURE AND RESULTANT STRONGER INSTABILITY
WILL REMAIN ALONG WARM FRONT INTO THIS AFTERNOON WITH MLCAPE OF
1000-2000 J/KG.

THUS FAR...MOST CONCENTRATED AREA OF TSTM DEVELOPMENT HAS BEEN
S-CNTRL ND WITHIN ZONE OF DEEP ASCENT N OF SURFACE LOW.
HOWEVER...WITH TIME THIS ACTIVITY MAY BEGIN TO DEVELOP EWD ALONG OR
JUST N OF WARM FRONT. LOW-LEVEL SHEAR IS NOT PARTICULARLY
STRONG...BUT THE PRESENCE OF THE MOIST/LOW LCL AIR MASS COUPLED WITH
SUFFICIENT DEEP-LAYER SHEAR FOR SUPERCELLS SUGGESTS SOME TORNADO
THREAT IN ADDITION TO HAIL AND DAMAGING WINDS.

..MEAD.. 06/18/2009


ATTN...WFO...DLH...MPX...FGF...ABR...BIS...

[Dave]

MESOSCALE DISCUSSION 1205
NWS STORM PREDICTION CENTER NORMAN OK
1248 PM CDT THU JUN 18 2009

AREAS AFFECTED...ERN KY AND TN...WRN NC INTO THE MTNS OF SC...AND
NRN GA

CONCERNING...SEVERE THUNDERSTORM WATCH 461...

VALID 181748Z - 181845Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 461
CONTINUES.

THE THREAT FOR DAMAGING STRAIGHT LINE WINDS AND SOME LARGE HAIL IS
EXPECTED TO CONTINUE ACROSS ERN KY AND TN...WRN NC INTO THE MTNS OF
SC...AS WELL AS NRN GA. LATE MORNING/EARLY AFTERNOON RADAR TRENDS
INDICATE THAT FORWARD PROPAGATING QLCS IS BEGINNING TO WEAKEN
SLIGHTLY AS IT MOVES INTO ERN KY AND WRN NC...WHERE ONLY MODEST
SURFACE HEATING AND DEWPOINTS ARE OBSERVED. HOWEVER...THE SRN FLANK
OF THIS MCS HAS EXPERIENCED A BURST IN CONVECTIVE
DEVELOPMENT...LIKELY DUE TO COLD POOL/GUST FRONT INTERACTION WITH
STRONGLY UNSTABLE ENVIRONMENT /MLCAPE VALUES OF 3000-4000 J PER KG/.
THESE LARGE INSTABILITY VALUES EXTEND SOUTHWARD THROUGH GA...AND ARE
COINCIDENT WITH A THERMAL AND MOISTURE AXIS/GRADIENT. GIVEN THE
POSITION OF AN UPPER LEVEL HIGH OVER LA...BELT OF MODERATELY STRONG
/30-40 KT PER AREA VWP DATA/ NNWLY MID LEVEL FLOW FROM TN S INTO GA
WILL RESULT IN FAVORABLE DEEP LAYER SHEAR FOR STORM MAINTENANCE AND
CONTINUED FORWARD PROPAGATION. IF STORM PROPAGATION CONTINUES TO
OCCUR IN THE DIRECTION OF INSTABILITY AXIS OVER GA...THEN A
CONCENTRATED CORRIDOR OF DAMAGING WIND GUSTS WILL BE FAVORED...ALONG
WITH SOME THREAT FOR LARGE HAIL.

..GARNER.. 06/18/2009


ATTN...WFO...CAE...GSP...MRX...JKL...FFC...LMK...OHX...BMX...
HUN...

[brunota2003]

Looking at the radar, it kinda looks like that PDS watch might bust, unless another group of storms form.

[Dave]

Looking at the radar, it kinda looks like that PDS watch might bust, unless another group of storms form.

I'm seeing the same thing you are, nothing really. Got a little development up in the dakota's, a few meso's scattered around the rest of the US but nothing solid.

[Dave]

[Dave]

MESOSCALE DISCUSSION 1207
NWS STORM PREDICTION CENTER NORMAN OK
0117 PM CDT THU JUN 18 2009

AREAS AFFECTED...ERN IA INTO CNTRL IL

CONCERNING...SEVERE THUNDERSTORM WATCH 462...

VALID 181817Z - 181945Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 462
CONTINUES.

THE THREAT FOR MAINLY DAMAGING WINDS AND HAIL CONTINUES WITH ONGOING
STORM OVER CNTRL PART OF WW AREA. ADDITIONAL TSTM DEVELOPMENT IS
POSSIBLE UPSTREAM OVER ERN IA LATER THIS AFTERNOON.

AS OF 18Z...RADAR IMAGERY INDICATED A STORM WITH A HISTORY OF
PRODUCING SEVERE HAIL AND WIND DAMAGE OVER HENRY COUNTY IL MOVING
305/35-40 KT. LATEST MESOANALYSIS SUGGESTS THAT THIS STORM REMAINS
DISPLACED TO THE NE OF COMPOSITE OUTFLOW BOUNDARY WITH IMMEDIATE
DOWNSTREAM SURFACE TEMPERATURES STILL IN THE 70S. HOWEVER DSM VWP
AND WINCHESTER IL PROFILER INDICATE THE PRESENCE OF WAA OCCURRING
NEAR AND E OF SURFACE BOUNDARY ALONG AXIS OF 20-30 KT SWLY/WSWLY
LLJ. THUS...ONGOING STORM WILL LIKELY CONTINUE TO INGEST SLIGHTLY
ELEVATED PARCELS ORIGINATING FROM WARM/MOIST LOW-LEVEL AIR MASS IN
PLACE OVER THE LOWER MO VALLEY. VERTICAL SHEAR WILL REMAIN
FAVORABLE FOR UPDRAFT ORGANIZATION/ROTATION WITH SEVERE THREAT
SPREADING SEWD INTO CNTRL IL.

STRENGTHENING LOW-LEVEL WAA IN ADVANCE OF MIDLEVEL SHORT WAVE TROUGH
CRESTING THE RIDGE AXIS OVER SD/NEB MAY SUPPORT ADDITIONAL UPSTREAM
STORM DEVELOPMENT THIS AFTERNOON N OF PRIMARY SURFACE BOUNDARY OVER
WRN PORTION OF WW AREA.

..MEAD.. 06/18/2009

[Dave]

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 464
NWS STORM PREDICTION CENTER NORMAN OK
220 PM EDT THU JUN 18 2009

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

DISTRICT OF COLUMBIA
PART OF DELAWARE
PART OF MARYLAND
MUCH OF EASTERN VIRGINIA
COASTAL WATERS

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 220 PM UNTIL
900 PM EDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 70
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 5 MILES NORTHEAST OF
SALISBURY MARYLAND TO 30 MILES NORTH NORTHWEST OF SOUTH HILL
VIRGINIA.

DISCUSSION...THUNDERSTORMS INCREASING IN NUMBER AND INTENSITY ACROSS
THE WATCH AREA AS AIR MASS NOW VERY UNSTABLE WITH MLCAPES AOA 2000
J/KG. AS STORMS DEVELOP INTO LINE SEGMENTS...DAMAGING WINDS WILL BE
A THREAT ALONG WITH HAIL.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 26025.


...HALES

Hazard Tornadoes EF2+ Tornadoes
Likelihood Low Very Low
Severe Wind 65 kt+ Wind
Moderate Moderate
Severe Hail 2"+ Hail
Moderate Low

[Dave]

This was issued a couple hours ago...

PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1201 PM CDT THU JUN 18 2009

...WIDESPREAD SEVERE THUNDERSTORMS ARE EXPECTED OVER PARTS OF THE
UPPER MISSISSIPPI VALLEY AND MIDWEST AS WELL AS THE SOUTHERN
APPALACHIANS THIS AFTERNOON AND TONIGHT...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
DEVELOPMENT OF TORNADOES...LARGE HAIL AND DAMAGING WINDS OVER PARTS
OF THE UPPER MISSISSIPPI VALLEY AND MIDWEST THIS AFTERNOON AND
TONIGHT. WIDESPREAD WIND DAMAGE IS ALSO POSSIBLE ACROSS THE SRN
APPALACHIANS THIS AFTERNOON.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE

NORTHEASTERN GEORGIA
MUCH OF IOWA
NORTHERN ILLINOIS
NORTHWESTERN INDIANA
SOUTHEASTERN KENTUCKY
SOUTHERN MINNESOTA
WESTERN NORTH CAROLINA
WESTERN SOUTH CAROLINA
FAR EASTERN SOUTH DAKOTA
EASTERN TENNESSEE
SOUTHERN WISCONSIN

ELSEWHERE...SEVERE STORMS ARE ALSO POSSIBLE FROM THE CENTRAL AND
NORTHERN PLAINS...EASTWARD TO THE MID ATLANTIC STATES AND SOUTHWARD
INTO FL.

A VERY ACTIVE THUNDERSTORM PATTERN WILL CONTINUE TODAY OVER AN
EXTENSIVE REGION FROM THE NORTHERN/CENTRAL PLAINS EASTWARD TO THE
MID ATLANTIC STATES AND SOUTHWARD INTO FLORIDA.

ONE SEVERE THUNDERSTORM CLUSTER WAS ALREADY ONGOING IN EASTERN
KENTUCKY THIS MORNING...AND IS EXPECTED TO TRACK SOUTHEASTWARD
THROUGH THE SOUTHERN APPALACHIANS...WITH WIDESPREAD WIND DAMAGE
POSSIBLE.

OTHER VIGOROUS THUNDERSTORM DEVELOPMENT IS EXPECTED LATER THIS
AFTERNOON OVER PORTIONS OF NEBRASKA...SOUTH DAKOTA...SOUTHERN
MINNESOTA AND IOWA. THIS REGION IS LOCATED WITHIN A ZONE OF MODEST
MID-LEVEL WINDS...AND A VERY MOIST AND UNSTABLE AIR MASS. ONCE
STORMS DEVELOP...THIS ENVIRONMENT WILL BE SUPPORTIVE OF INTENSE
SUPERCELLS...WITH A THREAT FOR VERY LARGE HAIL AND WINDS. TORNADOES
ARE ALSO EXPECTED...ESPECIALLY WHERE INDIVIDUAL THUNDERSTORM CELLS
TRACK ALONG OUTFLOW BOUNDARIES FROM EARLIER STORM COMPLEXES. THIS
EVENING...CLUSTERS OF SEVERE STORMS WILL MERGE INTO ONE OR MORE
COMPLEXES. AS THESE LARGER STORM COMPLEXES SHIFT EASTWARD
OVERNIGHT...A THREAT FOR WIDESPREAD...AND POSSIBLY SIGNIFICANT WIND
DAMAGE...IS ANTICIPATED ACROSS PORTIONS OF THE WESTERN GREAT LAKES.

STATE AND LOCAL EMERGENCY MANAGERS ARE MONITORING THIS POTENTIALLY
VERY DANGEROUS 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.

..IMY.. 06/18/2009