STORM2K

Models are currently suggesting a potentially severe outbreak this weekend across the Midwest, perhaps from Arkansas to the Canadian border. There is so much uncertainty at this point but the models point to something big...

If you see the thread I posted earlier today, my NWS office were weather journalists in tonight's Hazards Weather Outlook. They did not want to stop writing. Two good-sized paragraphs on an event four days away! It is definitely something to watch because usually the outter periods only have a sentence or two in the HWO.

What does this weekend, especially Saturday have in store for Saturday for Texas? Around the Mexia area. I am getting married and am hoping for stable weather.... I haven't had a chance to look at maps/forecasts, etc.

Thanks.

Kel

Kelarie wrote:What does this weekend, especially Saturday have in store for Saturday for Texas? Around the Mexia area. I am getting married and am hoping for stable weather.... I haven't had a chance to look at maps/forecasts, etc.

Thanks.

Kel

Too far south for the severe weather from what I can see.

I am calling for a potentially major severe weather outbreak on Saturday. The affected area will includa places like Omaha, Des Moines, Mankato, Marshall and Minneapolis MN. Maybe as far north as St Cloud MN or as far NW as Moorhead MN. Kansas City looks like will be the point of the furthest south these storms will form.

Right now I will say this: This could be the biggest severe weather outbreak since April 7. In fact, I think it will be. We are going to have dynamics in place that havent been around for a long time. The main question at this point is low level moisture.

Dew Points are currently only in the 50s all the way to texas...not good for severe wx prospects. However, given a intense low level jet for several days with this system and constant warm air advection, I expect at least dews around 60 in my highest threat areas. This may proove to low for a tornado outbreak, but given the extreme shear any cell will be capable of producing a tornado. Another possible higher threat is wind damage. Given intense ejection speed...expect a squall line to form by early afternoon in eastern SD-NE, this line will race northeast probably at 50-60 MPH reaching the MPLS metro by saturday evening. If any cellular convection forms as opposed to a squall line, a long track tornado would be possible. Ill monitor the event and make a risk map either tonight or tomorrow morning. Im interested as to what SPC will say...

Leaning towards the damaging wind idea at this point. Intense ejection speed not seen in a long time will take place on Saturday. This is probably the strongest september storm in this area in years. All factors considered...a widespread wind event with isolated tornadoes is probable. the Highest threat area for tornadoes should be in southern MN closest to the surface low..but that should be minimal given lack of extreme instability and intense undirectional shear likely. Other tornadoes will be possible especially in western IA ahead of the main cold front if a supercell can develop and get moist inflow. But this isnt looking like a good chance. Overall, I expect a large squall line extending from MN to perhaps western MO by evening capable of wind damage anywhere along it, but especially across IA and MN. This line will reach western WI by night time capable of wind damage still, but this threat should descrease gradually after dark..eventually diminishing in central WI.

Right now it is a very tough call. The setup seems reminiscent of November 10, 2002, adjusted to the west.

Still looking good for tomorrow afternoon/evening. Current outlook is at 30-hatched for severe in general. SPC discussion (below) mentions DP in the 60s with CAPE aproaching 2000 . . . ain't too bad for mid-September. Also mention the possible need for an upgrade to "A MODERATE RISK/HIGHER SEVERE PROBABILITIES." Should be fun to watch tomorrow.

Already some activity taking place in the Plains. Tornado watch out for Nebraska/Kansas. I think there is a chance the SPC could go Moderate for tonight.

The parameters are getting wild. Also the tornadoes in SW Kansas are getting better even as it approaches midnight there.

I am near KCMO. We don't have a chance of rain until Sat. night. I heard a night or two ago of a slight risk for severe weather here over the weekend.

Kristi

simplykristi wrote:I am near KCMO. We don't have a chance of rain until Sat. night. I heard a night or two ago of a slight risk for severe weather here over the weekend.

Kristi

They must be expecting a bunch of supercells in central Kansas to dissipate...

Very large area of Moderate Risk...could see a High Risk perhaps?

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CDT SAT SEP 16 2006

VALID 161200Z - 171200Z

...THERE IS A MDT RISK OF SVR TSTMS THIS AFTN AND EVE ACROSS PARTS
OF THE N CNTRL PLAINS/MID MO VALLEY...WHERE AN OUTBREAK OF SEVERE
STORMS APPEARS LIKELY...INCLUDING A FEW TORNADOES. THIS INCLUDES
PARTS OF ERN SD...SW MN...ERN NEB...WRN IA AND EXTREME NW MO....

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA
ACROSS MUCH OF THE NRN/CNTRL PLAINS INTO THE UPPER HALF OF THE MS
VALLEY....

MODELS INDICATE THAT A VERY STRONG MID/UPPER JET...NOW DIGGING INTO
THE BASE OF A BROAD WESTERN U.S. TROUGH...WILL NOSE OUT OF THE BASE
OF THE TROUGH INTO/THROUGH THE CENTRAL PLAINS AND UPPER MISSISSIPPI
VALLEY BY 12Z SUNDAY. THIS IS FORECAST TO BE ACCOMPANIED BY STRONG
LOW/MID-LEVEL CYCLOGENESIS OVER THE NORTHERN PLAINS LATER
TODAY/TONIGHT. A FAIRLY BROAD DEEP SURFACE TROUGH IS ALREADY
PRESENT THROUGH MUCH OF THE PLAINS...ALONG WITH A STRONG SOUTHERLY
LOW-LEVEL JET...WHICH IS SUPPORTING A RETURN FLOW OF GULF MOISTURE.
WHILE IT SEEMS UNLIKELY THAT THE VERY MOIST BOUNDARY LAYER WITH
LOWER/MID 70S DEW POINTS...NOW ADVECTING INTO SOUTHEAST TEXAS...WILL
BECOME INVOLVED LATER TODAY...A NARROW TONGUE OF MID 60S DEW POINTS
IS ALREADY AS FAR NORTH AS THE NORTH CENTRAL PLAINS. THIS SHOULD
CONTRIBUTE TO SUFFICIENT DESTABILIZATION FOR WIDESPREAD CONVECTIVE
DEVELOPMENT ACROSS MUCH OF THE CENTRAL/NORTHERN PLAINS INTO THE
UPPER MISSISSIPPI VALLEY DURING THIS FORECAST PERIOD. AN OUTBREAK
OF SEVERE STORMS IS EXPECTED THIS AFTERNOON AND EVENING...INCLUDING
THE RISK FOR A FEW TORNADOES...IN ADDITION TO LARGE HAIL AND
DAMAGING WINDS.

ELSEWHERE...IN RESPONSE TO DEVELOPING UPSTREAM PATTERN...AN UPPER
TROUGH ALONG THE ATLANTIC SEABOARD WILL BEGIN TO ACCELERATE OFFSHORE
TODAY. THIS FEATURE MAY STILL POSE A RISK OF THUNDERSTORM ACTIVITY
ALONG MID ATLANTIC COASTAL AREAS...WITH BETTER POTENTIAL FOR
CONVECTION IN LINGERING MOIST UNSTABLE AIR MASS OVER THE SOUTHERN
FLORIDA PENINSULA.

...CENTRAL PLAINS...
CONVECTIVE DEVELOPMENT MAY BE ONGOING AT THE BEGINNING OF THE
FORECAST PERIOD ACROSS PARTS OF THE DAKOTAS AND THE UPPER HALF OF
THE MISSISSIPPI VALLEY...ASSOCIATED WITH IMPULSES ALREADY
PROGRESSING THROUGH CYCLONIC FLOW REGIME TO THE LEE OF THE ROCKIES.
ACTIVITY IS EXPECTED TO BE IN THE PROCESS OF WEAKENING AND LIFTING
NORTHWARD...WITH A MID-LEVEL DRY SLOT NOSING NORTHEAST THROUGH THE
CENTRAL PLAINS...ALONG/SOUTH OF STRONG JET STREAK ASSOCIATED WITH
UPSTREAM SHORT WAVE TROUGH. THIS SHOULD ALLOW CONSIDERABLE HEATING
AND DESTABILIZATION OF MOIST WARM SECTOR AIR MASS ACROSS THE CENTRAL
PLAINS.

INITIATION OF VIGOROUS CONVECTIVE DEVELOPMENT MAY OCCUR IN EXIT
REGION OF UPPER JET...NEAR DEEPENING SURFACE LOW...ACROSS PARTS OF
CENTRAL SOUTH DAKOTA BY OR SHORTLY AFTER 18Z. EVOLUTION INTO A LINE
OR CLUSTER IN CYCLONIC ARC OF STRONGER MID-LEVEL FORCING IS THEN
EXPECTED NORTHEASTWARD THROUGH THE REMAINDER OF THE EASTERN
DAKOTAS/MINNESOTA...WHERE CAPE IN EXCESS OF 1000 J/KG AND STRONG
SHEAR WILL BE SUPPORTIVE OF SUPERCELLS. CONSIDERABLE LARGE HAIL IS
LIKELY...IN ADDITION TO A RISK FOR ISOLATED TORNADOES AND DAMAGING
WINDS.

ADDITIONAL CONVECTIVE DEVELOPMENT IS EXPECTED BY LATE THIS AFTERNOON
ACROSS THE MID MISSOURI VALLEY...SOUTHEAST OF OCCLUDING SURFACE
CYCLONE...WHERE COLD FRONT SHOULD MERGE WITH DRYLINE. STRONG
VERTICAL SHEAR AND CAPE ON THE ORDER OF 2000 J/KG WILL BE SUPPORTIVE
OF SUPERCELLS...WHICH PROBABLY WILL INITIALLY REMAIN
DISCRETE...BEFORE FORCING EVENTUALLY SUPPORTS A SQUALL LINE WHICH
MAY EXTEND SOUTHWARD THROUGH THE EAST CENTRAL PLAINS AND OZARKS BY
THIS EVENING. LARGE HAIL AND DAMAGING WINDS ARE LIKELY. A FEW
TORNADOES ARE ALSO EXPECTED...PARTICULARLY WITH STORMS CROSSING A
LINGERING CONVECTIVE BOUNDARY/WARM FRONT NEAR THE MISSOURI RIVER
...ACROSS EASTERN NEBRASKA/WESTERN IOWA. THIS IS WHERE LARGE
CLOCKWISE CURVED HODOGRAPHS ARE LIKELY TO EXIST BENEATH A 40-50 KT
SOUTHERLY LOW-LEVEL JET.

TORNADO POTENTIAL MAY DECREASE BY 02-03Z...BUT DAMAGING WIND/HAIL
POTENTIAL WITH EVOLVING SQUALL LINE MAY PERSIST INTO LATE EVENING
BEFORE CONVECTION WEAKENS.

..KERR/TAYLOR.. 09/16/2006

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
CURRENT UTC TIME: 0601Z (2:01AM), RELOAD THIS PAGE TO UPDATE THE TIME

We are not expecting severe weather here in the metro area of KC this weekend. Today's high is going to be 90.

Kristi

simplykristi wrote:We are not expecting severe weather here in the metro area of KC this weekend. Today's high is going to be 90.

Kristi

I really have doubts about that...

NEW SPC update: larger MDT, large area of 15%-hatched for tornadoes:

SPC AC 161635

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1135 AM CDT SAT SEP 16 2006

VALID 161630Z - 171200Z

...THERE IS A MDT RISK OF SVR TSTMS THIS AFTN AND EARLY TNGT ACROSS
SERN ND...ERN SD AND ERN NEB INTO W CENTRAL AND SWRN MN INTO WRN
IA....

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM
THE NRN PLAINS AND MN SWD AND SWWD INTO PARTS OF OK AND NWRN TX....

SIGNIFICANT SEVERE WEATHER OUTBREAK IS EXPECTED THIS AFTERNOON AND
EARLY TONIGHT OVER PARTS OF ERN SD AND NERN NEB...INTO SWRN MN AND
WRN IA.

...SYNOPSIS...
LARGE MID/UPPER LEVEL TROUGH COVER MUCH OF THE WRN U.S. THIS
MORNING. MID/UPPER LEVEL LOW OVER ID/MT WILL MOVE EWD INTO WRN ND
DURING THE PERIOD. LATEST WATER VAPOR SATELLITE IMAGERY SHOWS
STRONG SHORTWAVE/ASSOCIATED VORTICITY MAX CURRENTLY EAST OF NRN UT.
THIS FEATURE IS FORECAST TO MOVE ENEWD INTO NERN SD/SERN ND TONIGHT
BRINGING STRONG DYNAMIC FORCING INTO THE AREA. THIS WILL ALSO
ENHANCE STRONG SURFACE CYCLOGENESIS ALONG THE CENTRAL NEB/SD BORDER
BY MID AFTERNOON WHICH WILL FOCUS AREA OF STRONG/SEVERE CONVECTION
JUST EAST OF THE SURFACE LOW DEVELOPMENT.

...MUCH OF THE MIDDLE MO VALLEY REGION...

STRONG DYNAMIC FORCING ALONG WITH FAVORABLE KINEMATICS AND MODERATE
THERMODYNAMICS WILL BE PHASING TOGETHER VERY WELL ACROSS THIS AREA
THIS AFTERNOON. MORNING RAOB DATA SHOWED 50-60 KT SLY LOW LEVEL JET
FROM W CENTRAL OK NEWD THRU NERN KS THEN NWD OVER THE MSP AREA.
MEANWHILE...500 MB JET OF 80-90 KT WAS CYCLONICALLY ROUNDING THE MID
LEVEL TROUGH FROM W CENTRAL NV THRU CENTRAL UT AND NERN CO INTO SWRN
NEB AS THE UPPER LEVEL JET MIRRORED THE MID LEVEL FLOW FROM SFO BAY
AREA THRU NRN AZ INTO SERN NEB. ALL THIS ESTABLISHES VERY FAVORABLE
VERTICAL SHEAR/PROFILES ACROSS THE CENTRAL/NRN PLAINS. AT 15Z...AIR
MASS WAS DESTABILIZING RAPIDLY FROM CENTRAL KS INTO CENTRAL NEB.
SURFACE DEW POINTS WERE IN THE LOW/MID 60S AND MUCAPE WAS ALREADY
REACHING 3000 J/KG OVER WRN OK TO 2500 J/KG AS FAR NORTH AS N
CENTRAL NEB.

SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER PARTS OF CENTRAL
SD INTO S CENTRAL ND BY MID AFTERNOON AS EXIT REGION OF MID/UPPER
LEVEL JET COUPLES WITH WRN PARTS OF STRONG LOW LEVEL JET. SURFACE
DRYLINE WILL ALSO BE PUNCHING INTO CENTRAL/NERN NEB AT THIS TIME
PROVIDING STRONG UPWARD ASCENT WITHIN THE BOUNDARY LAYER. DEEP
LAYER SHEAR WILL BE 60-70 KT ACROSS THIS REGION AND SBCAPE BETWEEN
2000-3000 J/KG. THIS WILL BE SUPPORTIVE OF NUMEROUS SUPERCELLS EAST
OF SURFACE LOW INTENSIFICATION. THUS...TORNADOES...LARGE HAIL AND
DAMAGING WINDS ARE EXPECTED ACROSS ERN SD INTO SWRN MN LATE THIS
AFTERNOON.

...SRN FL PENINSULA...

VERY WARM MOIST AIR MASS IS PRESENT ALONG WITH ELY FLOW ACROSS
CENTRAL/SRN FL PENINSULA. MUCAPE RANGES FROM 2500-3000 J/KG THIS
MORNING/EARLY AFTERNOON. ELY FLOW USUALLY FAVORS SEA BREEZE
DEVELOPMENT ALONG THE ERN COAST MOVING WWD DURING MID AFTERNOON.
THUS...ISOLATED HAIL AND DAMAGING WINDS COULD OCCUR ACROSS THIS AREA
THIS AFTERNOON.

..MCCARTHY/JEWELL.. 09/16/2006

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
CURRENT UTC TIME: 1643Z (12:43PM), RELOAD THIS PAGE TO UPDATE THE TIME

We are in a slight risk for severe weather.

The moderate risk is for SE ND, eastern ND and NE, SW MN and western IA.

Kristi

i'm in the 30% wind/hail and 5% tornado with the moderate risk just to my west. looks like another big day for tornadoes maybe around Sioux Falls area...

I may be out in SW MN today

MESOSCALE DISCUSSION 1972
NWS STORM PREDICTION CENTER NORMAN OK
0125 PM CDT SAT SEP 16 2006

AREAS AFFECTED...SERN ND...ERN/CNTRL SD...SWRN MN...EXTREME NERN NEB
AND EXTREME NWRN IA

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

VALID 161825Z - 162100Z

WATER VAPOR IMAGERY SHOWS THAT THE 70+ KT H5 JET STREAK OVER CO WAS
BEGINNING TO SPREAD NEWD INTO SWRN NEB. STRONG ASCENT WAS ALREADY
EVIDENT WITHIN THE EXIT REGION OF THIS JET PER DEVELOPMENT OF
MID-LEVEL CONVECTION ACROSS SCNTRL SD. OTHERWISE...LOWER CLOUDS
WERE BEGINNING TO ERODE AND SHOULD ALLOW SFC TEMPERATURES TO BEGIN
INCREASING MORE RAPIDLY THROUGH LATE AFTN.

998 MB SFC LOW WILL BEGIN TO INTENSIFY INVOF OF KPIR THROUGH LATE
AFTN WITH SFC WINDS LIKELY BACKING. RESULTANT SFC CONVERGENCE AND
THE CONTINUED HEATING WILL INCREASE THE PROBABILITY FOR STORM
INITIATION AFTER 20-21Z. THIS WILL PRIMARILY OCCUR FROM PARTS OF
SERN ND SWD INTO ERN SD AND EXTREME NERN NEB.

FORECAST 2-8KM SHEAR VECTORS WILL REMAIN SUFFICIENTLY NORMAL TO THE
INITIATING BOUNDARY TO SUPPORT DISCRETE STORM STRUCTURES. GIVEN THE
INCREASE IN VERTICAL SHEAR...THESE SUPERCELLS COULD BE LONG-LIVED AS
THEY MATURE ACROSS ERN SD THIS EVENING. THE BACKED FLOW WILL
AUGMENT THE LOW-LEVEL HODOGRAPHS RESULTING IN 0-1KM HELICITY
SUFFICIENTLY STRONG FOR TORNADOES...ESPECIALLY GIVEN THE LOW LCL/S.
OTHERWISE...LARGE HAIL AND DAMAGING WINDS WILL BE LIKELY.

ACTIVITY MAY EVOLVE INTO LINE SEGMENTS AND MOVE INTO WCNTRL MN LATER
THIS AFTN WITH A CONTINUED THREAT FOR DAMAGING WINDS. FARTHER
S...TSTMS COULD REMAIN DISCRETE LONGER ACROSS SWRN MN AND NWRN IA
WHERE H5-H3 Q-VECTOR CONVERGENCE WILL BE WEAKER /FEWER STORMS/ AND
SHEAR VECTORS MORE NORMAL TO THE BOUNDARY. THAT REGION WILL ALSO BE
LOCATED ALONG THE NOSE OF A STRENGTHENING THERMAL RIDGE/ STRONGER
INSTABILITY.

..RACY.. 09/16/2006

Could be a PDS watch shortly?