Severe Weather Risk - May 7 Thurs

[venture]

Instability will be increase across the area tomorrow, though storm coverage is not expected to be widespread in our area. Here is the current outlook...







DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0106 AM CDT WED MAY 06 2009

VALID 071200Z - 081200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN PORTIONS OF THE
CENTRAL/SRN PLAINS THROUGH THE OH/TN VALLEYS...AND CENTRAL GULF
COAST STATES TO CAROLINAS/SERN VA...

...SYNOPSIS...
MODELS ARE IN GENERAL AGREEMENT WITH THE EVOLUTION OF THE MID/UPPER
LEVEL FLOW REGIME ACROSS THE CONUS ON DAY 2 /THU/. ONE SHORTWAVE
TROUGH...CURRENTLY LOCATED ACROSS SRN SASKATCHEWAN PER WATER VAPOR
IMAGERY...WILL PROGRESS EWD THURSDAY INTO NRN ONTARIO WITH SOME
AMPLIFICATION/HEIGHT FALLS ACROSS THE GREAT LAKES REGION.
MEANWHILE...THE NERN PACIFIC CLOSED LOW SHOULD BE MOVING INLAND OVER
SRN BC/WA AS AN OPEN WAVE WITH THIS SYSTEM AMPLIFYING SEWD ACROSS
THE NRN ROCKIES/HIGH PLAINS ON DAY 2. SEVERAL WEAKER MID LEVEL
IMPULSES ARE EXPECTED TO TRAVERSE THE FAST WNWLY FLOW ALOFT THROUGH
THIS FORECAST PERIOD AND WILL BE THE IMPETUS FOR TSTM DEVELOPMENT.
WNWLY MID/UPPER LEVEL WINDS ARE FORECAST TO BECOME MORE ZONAL BY 12Z
FRIDAY FROM THE NRN GREAT BASIN/CENTRAL ROCKIES TO THE OH VALLEY AS
HEIGHTS FALL ACROSS THE INTERMOUNTAIN WEST.

...CENTRAL OK/ERN KS TO LOWER OH/TN VALLEYS THU AFTERNOON/NIGHT...
MID LEVEL IMPULSE LOCATED AT 39N 139W...AND NOW APPROACHING NRN
CA/ORE...WILL MOVE INLAND THROUGH THE NRN INTERMOUNTAIN WEST
TODAY...AND SHOULD REACH NEB BY START OF DAY 2 AS IT TRANSLATES
ESEWD WITHIN FAST WNWLY MID LEVEL FLOW. THIS MID LEVEL FEATURE AND
ANOTHER POSSIBLY OVER CO AT 12Z THURSDAY WILL PROGRESS ESEWD ACROSS
THE ERN PLAINS TO MO/OZARKS REGION AND WILL BE THE IMPETUS FOR TSTM
DEVELOPMENT THURSDAY AFTERNOON. AT THE SURFACE...A BOUNDARY IS
EXPECTED TO EXTEND ESEWD FROM NRN KS THROUGH NRN MO TO SRN IL...WITH
A SURFACE LOW TRACKING ALONG THIS FRONT INTO NERN KS/NWRN MO BY
08/00Z. A FRONT TRAILING SWD FROM THE LOW SHOULD EXTEND THROUGH
CENTRAL KS TO WRN/CENTRAL OK BY LATE AFTERNOON. MOISTURE RETURN
ACROSS THE WARM SECTOR /SURFACE DEWPOINTS IN THE 60S ACROSS KS/MO
AND LOWER 70S INTO OK COMBINED WITH SURFACE HEATING AND STEEP MID
LEVEL LAPSE RATES WILL RESULT IN MODERATE INSTABILITY ACROSS ERN
KS/MO AND VERY STRONG INSTABILITY OVER OK/NRN TX.

THE FAVORABLE THERMODYNAMICS COMBINED WITH INCREASING ASCENT AHEAD
OF THE MID LEVEL IMPULSE AND INCREASING EFFECTIVE BULK SHEAR /IN
EXCESS OF 50 KT/ WILL PROMOTE THE LIKELIHOOD FOR SUPERCELLS
PRODUCING TORNADOES AND VERY LARGE HAIL. MODELS SUGGEST THE
POTENTIAL FOR THIS ACTIVITY TO GROW UPSCALE INTO A FORWARD
PROPAGATING MCS ACROSS MO/NRN AR INTO THE LOWER OH VALLEY AS THE SLY
LLJ VEERS TO WLY AND STRENGTHENS TO 40-50 KT. DAMAGING WINDS WOULD
BE THE PRIMARY THREAT WITH THIS ACTIVITY OVERNIGHT.

[westsidesooner]

Finally back to spring. Tomorrow could be intersting. I'll really have to wait to see if the sun comes out before I get to specific with my foreecast/guess but if its sunny in the morning and theres no MCS messing things up we may have our first really good visual chase day. Do you think the cap will hinder things Venture?

[Thunder]

Cap? Don't jinx it, WSS!

[Charlie40]

Tomorrow looks like it possibly has potential but I am looking at Friday more than tomorrow.

[westsidesooner]

Sorry T-man I don't want to jinx it. And Charlie, Friday appears to be the more promising day. Agreed!!! The SPC already noted on their day 3 page that parts of Oklahoma may need to be upgraded to moderate for Friday. But sometimes the best day is the day before the big show. I'm concerned that a MCS may scour the atmosphere, or worse yet the front and/or dryline may progress faster than expected. I hope not. I haven't seen a good tower go up all spring yet. My camera is getting dusty. Too bad Vortex2 doesnt get rolling til next week.

SPC Day3 Quote


FARTHER SW...STRONG SURFACE HEATING ACROSS CENTRAL OK ALONG A DRY
LINE/SURFACE FRONT AND IN THE WAKE OF EARLY FRIDAY MORNING MCS WILL
SUPPORT A VERY UNSTABLE AIR MASS BY AFTERNOON...GIVEN HIGH MOISTURE
VALUES /SURFACE DEWPOINTS IN LOWER 70S/ AND STEEP MID LEVEL LAPSE
RATES. THE STEEP MID LEVEL LAPSE RATES WILL CAP THE OK AIR MASS
THROUGH MUCH OF THE AFTERNOON. STRONG SURFACE HEATING /INTO THE
MID-UPPER 80S/ COMBINED WITH ASCENT WITHIN ENTRANCE REGION OF
POTENTIAL MID LEVEL JETLET TRAVERSING OK/AR FRIDAY AFTERNOON MAY
PROVE SUFFICIENT FOR TSTM DEVELOPMENT WWD INTO CENTRAL OK AND
POSSIBLY FAR N TX. GIVEN THAT MODELS AGREE THAT STORMS WILL DEVELOP
INTO CENTRAL OK...WITH ECMWF/NAMKF INDICATING STORMS BY LATE
AFTERNOON...CONFIDENCE CONTINUES TO INCREASE WITH THE LIKELIHOOD FOR
SEVERE STORMS ACROSS MUCH OF CENTRAL AND ERN OK ON DAY 3. TORNADOES
AND VERY LARGE HAIL WOULD BE LIKELY WITH THIS ACTIVITY. AN INCREASE
IN A SWLY LLJ INTO OK FRIDAY NIGHT WILL SUPPORT ANOTHER MCS
SPREADING EWD INTO AR/OZARKS.

PARTS OF OK MAY REQUIRE AN UPGRADE TO HIGHER PROBABILITIES AND
MODERATE RISK IN LATER OUTLOOKS.

[Thunder]

I've noticed every time when we are suppose to get a really good outbreak, it was always doomed due to either early cloud cover, too much wind, or both.

So far, it has been a clear sky today, we'll see what tomorrow morning brings to us. However, sometime during the morning it looks promising for an active weather then bam, the clouds come out of nowhere and ruin it.

I would rather to have all the action tomorrow, that way I'll be at home to track it. lol

[Karried]

A really good outbreak might be fun for storm chasers but deadly for others.. so I'm okay that the storms are dissipating. I hope they continue to do so.

[jstanthrnme]

For Venture:

Weekend Meteorologist

[venture]

Ignore the graphics in the first post, since they are actually not for today anymore.



DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 AM CDT THU MAY 07 2009

VALID 071200Z - 081200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM OK/KS NEWD INTO THE WRN OH
VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS STRETCHING FROM THE MID
ATLANTIC STATES SEWD INTO THE GULF COAST STATES...

...SYNOPSIS...
WNWLY MID LEVEL WINDS AT 50-70 KT ARE FORECAST TO EXTEND FROM THE
PACIFIC NW INTO THE CENTRAL PLAINS AND EWD INTO THE MID ATLANTIC
STATES THROUGH THE PERIOD. WEAK EMBEDDED SHORTWAVE TROUGHS WILL
PROGRESS THROUGH THIS FLOW...THOUGH NONE OF THEM ARE FORECAST TO BE
STRONG ENOUGH TO RESULT IN HEIGHT FALLS OR AMPLIFY THE ZONAL FLOW.
AT THE SURFACE...A WEAK FRONT/REMNANT OUTFLOW BOUNDARY WILL LINGER
EAST OF THE APPALACHIANS SEWD INTO GULF COASTAL STATES. ANOTHER WEAK
COLD FRONT/TROUGH IS FORECAST TO EXTEND FROM THE WRN GREAT LAKES
SEWD INTO THE CENTRAL PLAINS BY LATE AFTERNOON.

...SERN KS/SWRN MO/NRN AND CENTRAL OK/NWRN AR...
MOIST BOUNDARY LAYER...DEWPOINTS AOA 70F...AND AFTERNOON HEATING
WILL LEAD TO A VERY UNSTABLE AIRMASS...MLCAPES IN EXCESS OF 3000
J/KG. HOWEVER...LACK OF ANY EVIDENT DYNAMICAL FORCING AND STRONG
CAPPING BETWEEN 800 AND 700 MB WILL LIKELY INHIBIT STORM DEVELOPMENT
THROUGH THE DAYLIGHT HOURS. SHOULD ANY STORMS FORM... DEEP LAYER
SHEAR AND INSTABILITY WOULD BE SUPPORTIVE OF SUPERCELLS WITH VERY
LARGE HAIL. HOWEVER...THUNDERSTORMS ARE MORE LIKELY OVERNIGHT AS
BOUNDARY SAGS SLOWLY SEWD INTO FAR SERN KS/SWRN MO/NRN OK AND LOW
LEVEL JET/WARM ADVECTION INTENSIFIES. GIVEN THE DEGREE OF
INSTABILITY...30-40 KT MID LEVEL WNWLY FLOW AND SURFACE
BOUNDARY...AN MCS WITH HAIL AND BOWING SEGMENTS/WIND APPEARS
LIKELY...MAINLY AFTER 05Z.

[venture]

Currently looks like any metro impacting activity will be isolated stuff that may break through the cap later today. Also the overnight MCS/MCC should stay north of the metro, though the northern sections could get brushed overnight. Don't be shocked to see some storms with high winds or large hail get close tonight, but main show looks like tomorrow (which pretty much means it won't happen tomorrow now ; ) ).

[westsidesooner]

Theres a lot of conflicting thoughts out there on today, tonight (not so much), and tomorrow. Or it could be just outdated graphics. It'll be interesting to see if the forecast come more into line at noon during their schedluled release. Lots of fog out there this morning but I think it'll burn off fairly quickly later this morning. I'm still thinking theres a chance of an isolated storm or two today across the body of the state. I don't know why....maybe its just a wishcast. The NWS and the SPC seem to have different opinions ATTM for today. But not by much. Intersting conflict noted on the NWS sight this morning. Time sensitve graphs below, so they wont make sense later.



This graph shows chances for all but NW oklahoma today
VS. the text version which excludes the SW 1/3 of Oklahoma.
Both of which don't concur with the SPC graph venture posted. hmmmm????

Hazardous Weather Outlook
HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE NORMAN OK
500 AM CDT THU MAY 7 2009

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
ACROSS PORTIONS OF OKLAHOMA.

LOCATION...
THE SLIGHT RISK COVERS LOCATIONS EAST OF A LINE EXTENDING FROM
FREEDOM...TO WEATHERFORD...TO PAULS VALLEY...TO ATOKA.

TIMING...
ALTHOUGH AN ISOLATED SEVERE STORM CANNOT BE RULED OUT LATE THIS
AFTERNOON OR EVENING...THE MOST LIKELY TIME FOR SEVERE THUNDERSTORMS
WILL BE AFTER MIDNIGHT.

IMPACTS...
DAMAGE TO AUTOMOBILES...VEGETATION...AND ROOFS FROM LARGE HAIL.
DAMAGING WIND GUSTS TO 70 MPH.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
RISK AREA SHOULD PLAN FOR SEVERE WEATHER OPERATIONS FROM LATE THIS
AFTERNOON UNTIL EARLY FRIDAY MORNING.

DISCUSSION...
WARM TEMPERATURES AND HIGH AMOUNTS OF MOISTURE WILL LEAD TO VERY
UNSTABLE CONDITIONS THIS AFTERNOON. HOWEVER...DUE TO A MODERATE
CAPPING INVERSION AND LACK OF ANY FOCUSING MECHANISMS...ANY STORMS
THAT FORM DURING THE HEAT OF THE DAY WILL BE ISOLATED

[Thunder]

Let it be known that 2009 is notorious for excess cloud cover on every storm day.