Area Forecast Discussion
Issued by NWS Des Moines, IA

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

000
FXUS63 KDMX 252039
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
339 PM CDT MON APR 25 2016

.SHORT TERM.../TONIGHT/
ISSUED AT 337 PM CDT MON APR 25 2016

STRATOCU DECK IN PLACE ACROSS THE NORTH WITH THE UPPER LOW SLOWLY
LIFTING NORTHEAST OF THE STATE. EXPECT SOME CLEARING INTO THE
EVENING HOURS...ACROSS THE NORTH WITH THE DECK TO BUILD BACK IN AS
STRATUS OVERNIGHT ACROSS THE NORTH/NORTHEAST. SOME WEAK LIFT WITH
HIGHER LOW LEVEL MOISTURE MAY LEAD TO SOME DRIZZLE JUST OFF TO THE
NORTH AND EAST OF THE CWA LATE TONIGHT. OTHERWISE WINDS TO DIMINISH
AND SHIFT AROUND TO THE EAST TOWARD EARLY TUESDAY. EXPECT TEMPS TO
FALL INTO THE UPPER 40S NORTH TO MID 50S SOUTH. SOMEWHAT CONCERNED
THAT TEMPS MIGHT STAY UP A BIT IN THE NORTH WITH THE CLOUDS...SO MAY
BE A BIT COOL IN THAT AREA.

.LONG TERM.../TUESDAY THROUGH MONDAY/
ISSUED AT 337 PM CDT MON APR 25 2016

ATTENTION FOR THE LONG TERM REMAINS FIXED ON SEVERE WX POTENTIAL
TUESDAY LATE AFTERNOON INTO WEDNESDAY. SEASONABLY STRONG UPPER LEVEL
TROUGH OVER THE INTER-MOUNTAIN WEST WILL CLOSE OFF AND MIGRATE
EASTWARD TONIGHT...ACQUIRING A NEGATIVE TILT AS IT LIFTS
NORTHEASTWARD OVER THE CENTRAL HIGH PLAINS TUESDAY AND WEDNESDAY.
THE 995 MB SURFACE CYCLONE REFLECTION WILL MOVE INTO KANSAS BY 00Z
WEDNESDAY WITH THE WARM FRONT DRAPED ALONG I-70 IN MISSOURI AND A
DRY LINE PUSHING ACROSS EASTERN KANSAS. THE 12Z GUIDANCE PACKAGE HAS
SLOWED THE SYSTEM SLIGHTLY COMPARED TO EARLIER RUNS AND SHIFTED THE
WARM FRONT FURTHER TO THE SOUTH...STRENGTHENING THE H800-H700 WARM
NOSE OVER IOWA THROUGH THE AFTERNOON AND OVERNIGHT HOURS. HAVE
TRENDED THE FORECAST IN THIS DIRECTION AND DELAYED POPS BY SEVERAL
HOURS.

THE THREAT FOR ANY NEAR-SURFACE BASED CONVECTION SHOULD BE LIMITED
TO THE FAR SOUTHWEST CORNER OF THE STATE. CONVECTION OVER NEBRASKA
IS EXPECTED TO GROW UPSCALE OVER THE COURSE OF THE EVENING INTO A
QLCS WITH THE POSSIBILITY OF A FEW ELEVATED SUPERCELLS DEVELOPING
JUST AHEAD OF THE LINE AS FALLING HEIGHTS HELP ERODE THE CAP. SHOULD
ANY ISOLATED CONVECTION DEVELOP...MUCAPE VALUES OF OVER 2000 J/KG
AND EFFECTIVE BULK SHEAR VALUES OF 30 TO 40 KTS WILL SUPPORT A LARGE
HAIL THREAT SOUTH OF HWY 34 AND WEST OF HWY 169 BETWEEN 01 AND 04Z.
WITH STRONG AND DEEP MOISTURE TRANSPORT INTO THE AREA...THE BIGGEST
SENSIBLE WEATHER THREAT IS LIKELY TO BE HEAVY RAINFALL WITH AMOUNTS
OF ONE TO TWO INCHES POSSIBLE IN SOUTHWEST IOWA.

THE LINEAR COMPLEX WILL LIFT NORTHEASTWARD ACROSS THE CWA THROUGH
WEDNESDAY MORNING...WEAKENING THROUGH THE NIGHT AS THE ELEVATED
INSTABILITY AND THETA-E FORCING WANES. ATTENTION THEN TURNS BACK TO
SOUTHERN IOWA FOR WEDNESDAY AFTERNOON AS THE SURFACE LOW PIVOTS
ACROSS SE NEBRASKA AND BEGINS TO SLIDE EASTWARD. THIS WILL BRING THE
SURFACE WARM FRONT AROUND THE IA/MO BORDER DURING PEAK
HEATING...WITH THE EC FURTHER NORTH THAN THE GFS. THE JUXTAPOSITION
OF THE UPPER LEVEL CYCLONE...STEEP LOW AND MID LEVEL LAPSE RATES...
AND SBCAPE VALUES 1500-2000 J/KG MAY YIELD A MULTI-FACETED SEVERE
WEATHER EVENT WITH THE POSSIBILITY OF LANDSPOUT TORNADOES NEAR ANY
RESIDUAL OUTFLOW BOUNDARIES OR THE MAIN SYNOPTIC FRONT.

THE UPPER LOW WILL ELONGATE ON THURSDAY AND DEPARTS LATE IN THE DAY
AS SHORTWAVE RIDGING BUILDS NORTHWARD FROM THE SOUTHERN PLAINS.
REMOVED THE TOKEN SLIGHT CHANCE POPS FOR THIS TIMEFRAME GIVEN GOOD
CONSENSUS ON THE POSITION OF THE RIDGE. THE PARADE OF SPRING
CYCLONES CONTINUES ON FRIDAY WITH ANOTHER LOW EJECTING ACROSS THE
SOUTHERN PLAINS. IOWA LOOKS TO REMAIN ON THE COLD SIDE OF THIS
WEEKEND SYSTEM WITH HIGHS ONLY IN THE 50S TO LOW 60S.

&&

.AVIATION.../FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON/
ISSUED AT 1231 PM CDT MON APR 25 2016

SOME LOW STRATOCU WITH MVFR CIGS EXPECTED TO LINGER ACROSS THE
NORTH THIS AFTERNOON...AND MAY FILL BACK IN ACROSS KALO AND KMCW
TONIGHT. OTHERWISE CLEARING SKIES FOR KFOD AND SOUTHERN TAF SITES
TONIGHT. WINDS TO BECOME LIGHT AND VARIABLE OVERNIGHT...SHIFTING
AROUND TO THE EAST FOR TUESDAY.


&&

.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BEERENDS
LONG TERM...SKOW
AVIATION...BEERENDS



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.