Iowa Weather Discussion May 19th 2013 (SEVERE WEATHER TODAY/MONDAY)

NO Video today due to Prior Obligations

SEVERE WEATHER DAYS: The Storm Prediction Center has a slight risk of severe weather for the entire state of Iowa Sunday. All modes of severe weather are possible including a few tornadoes. Here is SPC’s discussion on Sunday, …PLAINS/OZARKS/MO VALLEY TO MIDDLE/UPPER MS VALLEY…
A PLUME OF STEEP MID-LEVEL LAPSE RATES WILL REMAIN IN PLACE /AND-OR
QUICKLY BE REESTABLISHED FROM SATURDAY PM CONVECTION/ ACROSS MOST OF
THE CENTRAL/SOUTHERN PLAINS TO THE MIDDLE MS VALLEY. A RELATIVELY
MOIST AIRMASS WITH MIDDLE/UPPER 60S AND SOME LOWER 70S F SURFACE
DEWPOINTS WILL BE IN PLACE TODAY WITHIN THE WARM SECTOR TO THE EAST
OF A NORTH-CENTRAL PLAINS COLD FRONT AND SOUTHERN PLAINS DRYLINE.

AIDED BY A SUSTAINED LOW LEVEL JET/WARM ADVECTION…SCATTERED
CONVECTION WILL LIKELY BE ONGOING EARLY TODAY ESPECIALLY ACROSS THE
MIDDLE MO VALLEY AND UPPER MIDWEST. CONVECTIVE REMNANTS/OUTFLOW
BOUNDARIES WILL BE A POTENTIAL FACTOR FOR
REDEVELOPMENT/RE-INTENSIFICATION INTO THIS AFTERNOON FOR AREAS SUCH
AS THE UPPER MIDWEST/UPPER MS VALLEY WITHIN A RELATIVELY
MOIST/UNSTABLE AIRMASS ALONG/SOUTHWEST OF A NORTHWARD-SHIFTING WARM
FRONT.

SOUTH OF THE EARLY DAY/ONGOING ACTIVITY…STRONG HEATING/AGGRESSIVE
DESTABILIZATION WILL TAKE PLACE ESPECIALLY FROM PARTS OF THE
MIDDLE/LOWER MO VALLEY INCLUDING SOUTHEAST NEB/SOUTHERN IA
SOUTH-SOUTHWESTWARD TO THE EAST OF THE DRYLINE ACROSS OK AND
NORTH-CENTRAL/WEST-CENTRAL TX. HERE…MLCAPE VALUES ARE LIKELY TO
EXCEED 3000 J/KG. AIDED BY STEADY HEIGHT FALLS AND AN INCREASING
DEEP LAYER WIND FIELD /40-45 KT EFFECTIVE SHEAR/…SURFACE BASED
TSTM/DISCRETE SUPERCELL DEVELOPMENT APPEARS MOST PROBABLE TO
INITIALLY OCCUR ACROSS AREAS SUCH AS CENTRAL/NORTHEAST KS AND
SOUTHEAST NEB INTO FAR NORTHERN OK…PERHAPS BY EARLY OR
MID-AFTERNOON. FARTHER SOUTH…NEAR/SOUTH OF THE SURFACE
LOW/FRONT/DRYLINE INDUCED TRIPLE POINT…SOMEWHAT MORE
ISOLATED/HIGHER-BASED DEEP CONVECTIVE DEVELOPMENT IS ANTICIPATED BY
LATE AFTERNOON/EARLY EVENING ACROSS CENTRAL/SOUTHERN OK SOUTHWARD
INTO NORTH/WEST-CENTRAL TX.

WITH AID OF A DIURNALLY STRONG SOUTH-SOUTHWESTERLY LOW LEVEL
JET…FORECAST SHEAR PROFILES STRONGLY FAVOR LONG-LIVED SUPERCELLS
CAPABLE OF VERY LARGE HAIL…IN ADDITION TO TORNADOES /PERHAPS ONE
OR TWO STRONG/ ESPECIALLY WHERE DEWPOINTS HOLD IN THE UPPER
60S/LOWER 70S. BY EARLY/MID-EVENING…THE PROXIMITY OF THE SLOWLY
ADVANCING COLD FRONT AND BACKING MID-LEVEL FLOW SHOULD LEAD TO
UPSCALE QUASI-LINEAR DEVELOPMENT AND AN INCREASING DAMAGING WIND
THREAT ACROSS PARTS OF THE LOWER MO VALLEY/OZARKS AND MIDWEST.
MEANWHILE…NEAR THE DRYLINE…A MORE DISCRETE MODE OF SUSTAINED
SUPERCELLS /AGAIN SOMEWHAT HIGHER-BASED ESPECIALLY WITH SOUTHWARD
EXTENT/ CAPABLE OF LARGE HAIL WILL BE THE PRIMARY CONCERN…BUT A
LIMITED TORNADO THREAT AND SOME DAMAGING WIND POTENTIAL MAY EXIST AS
WELL DURING THE LATE AFTERNOON AND EVENING HOURS.

There is a slight risk of severe weather again on Monday for the eastern half of the state. Storms could be as significant as on Sunday with all modes of severe weather possible once again. This will be dependent on storms that may be ongoing Sunday night into early Monday morning. This is a particularly dangerous situation that may unfold across the state. Keep abreast of any changes on the blog, FB page and make sure you have a way to be able to get warnings either by a Mobile App on your phone or by weather radio.

REST OF WEEK AND INTO JUNE: The storm takes its time departing the state through at least Wednesday before we get some sunshine statewide and seasonal to slightly below seasonal readings heading toward the Memorial Day weekend. Saturday looks to be the best day of the holiday weekend with plenty of sunshine and temperatures a few degrees either side of 80. A new system approaches from the west Sunday into Memorial Day Monday that will bring shower and thunderstorm chances back to the state at that time. It’s too early to determine if there will be any severe weather with the activity as it is still a week out but we’ll keep an eye out as we watch further model runs. The first few days of June look to be warm and sunny with readings in the 80s if the GFS pans out.