Mesoscale Discussion 13

Issued

Jan 7, 2008, 7:26 AM CST (13:26 UTC)

Expired

Jan 7, 2008, 9:30 AM CST

In force

2 hr

Issued by

the Storm Prediction Center

The Quad Cities radar (KDVN), 76 km from the middle of the area, began a volume at 13:26 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

000 
ACUS11 KWNS 071326
SWOMCD
SPC MCD 071326 
WIZ000-ILZ000-IAZ000-MOZ000-071530-

MESOSCALE DISCUSSION 0013
NWS STORM PREDICTION CENTER NORMAN OK
0726 AM CST MON JAN 07 2008

AREAS AFFECTED...PARTS OF NRN MO...SRN IA...NW IL...SRN WI

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 071326Z - 071530Z

ADDITIONAL STORMS ARE POSSIBLE ACROSS PARTS OF SOUTHERN/EASTERN
IOWA...PERHAPS NORTHERN MISSOURI...THROUGH MID MORNING.

AN INITIAL CLUSTER OF THUNDERSTORMS...NOW DEVELOPING EAST
NORTHEASTWARD ALONG FRONTAL ZONE ACROSS SOUTHERN WISCONSIN...HAS
FORMED WELL IN ADVANCE OF MAIN FRONTAL WAVE...STILL LOCATED NEAR THE
OMAHA NEB AREA.  ACTIVITY PROBABLY IS BEING SUPPORTED BY FORCING
ASSOCIATED WITH A WEAK MID-LEVEL IMPULSE CURRENTLY LIFTING THROUGH
THE UPPER MISSISSIPPI VALLEY.  MODELS ARE SUGGESTIVE THAT THIS
FORCING MAY WEAKEN SHORTLY...BUT ANOTHER IMPULSE WITHIN THE CYCLONIC
SOUTHWESTERLY MID/UPPER FLOW REGIME IS ALREADY LIFTING NORTHEAST OF
THE CENTRAL PLAINS.  AND...IT APPEARS LARGE-SCALE FORCING WILL
INCREASE NEAR A STRENGTHENING SOUTHWESTERLY LOW-LEVEL JET TO THE
EAST OF LOW...ACROSS PARTS OF EXTREME NORTHERN MISSOURI/SOUTHERN
IOWA  BETWEEN NOW AND 15-16Z.  GIVEN THE PRESENCE OF WEAK
CONDITIONAL INSTABILITY IN THE VICINITY OF THE FRONTAL ZONE...AS
REFLECTED BY THE 12Z SOUNDING FROM DAVENPORT IA ...THIS IS EXPECTED
TO SUPPORT NEW THUNDERSTORM DEVELOPMENT.

WHILE RUC GUIDANCE INDICATES THAT DEEP LAYER SHEAR THROUGH THE
CONVECTIVE LAYER IS MARGINAL FOR UPDRAFT ROTATION...MOST UNSTABLE
CAPE OF 500-1000 J/KG COULD SUPPORT ADDITIONAL MARGINAL SEVERE HAIL
IN STRONGER CELLS.  ALTHOUGH...OBSERVED AND MODEL FORECAST SOUNDINGS
SUGGEST THE PRESENCE OF WEAK CONVECTIVE INSTABILITY ABOVE THE SHARP
INVERSION...POTENTIAL FOR DAMAGING DOWNDRAFTS PENETRATING THE STABLE
SURFACE BASED LAYER SEEMS LOW...AS DOES THE POTENTIAL FOR A DAMAGING
WIND PRODUCING GRAVITY WAVE TYPE OF EVENT.

..KERR.. 01/07/2008

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LOT...MKX...DVN...ARX...DMX...EAX...

40319437 40819429 41509325 42259230 42889120 43349018
43348901 43058798 42638802 42368883 41998974 41429063
40959141 40599241 40259325 40169408

Mesoscale Discussions in Iowa, 2008Mesoscale Discussions in Wisconsin, 2008Mesoscale Discussions in Illinois, 2008Every mesoscale discussion in 2008

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.