Area Forecast Discussion
Issued by NWS Des Moines, IA

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004
FXUS63 KDMX 101730
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1130 AM CST WED FEB 10 2016

...UPDATED AVIATION DISCUSSION...

.SHORT TERM /TODAY/...
ISSUED AT 330 AM CST WED FEB 10 2016

WEAK VORT MAX TO SHOVE SOUTHEASTWARD THROUGH THE STATE TODAY IN
NORTHWEST FLOW PATTERN ALOFT. CURRENTLY RESPONSIBLE FOR SOME LIGHT
SNOW ACROSS THE EASTERN DAKOTAS AND AN INCREASE IN CLOUD COVER
ACROSS WESTERN IOWA. ASSOCIATED SFC LOW OVER THE WESTERN DAKOTAS/ERN
MONTANA TO SLIDE SOUTHEASTWARD INTO THE CENTRAL PLAINS TODAY. WAA
AHEAD OF THE SFC LOW TO BE IN PLACE ACROSS THE WESTERN HALF OF THE
CWA...WITH THE VORT MAX SHEARING APART SOME AS IT DROPS SOUTHEAST.
THEREFORE EXPECT DECENT CHANCE FOR SNOW WITH THE WAVE INTO THE
WESTERN/NORTHWESTERN CWA THIS MORNING...WITH CHANCES WANING ACROSS
THE SOUTHWEST/SOUTH CENTRAL THIS AFTERNOON. EXPECT A BAND OF LIGHT
TO MODERATE SNOW AT TIMES...WITH AROUND A HALF AN INCH MAYBE AN INCH
AND A HALF POSSIBLE AT LOCATIONS ACROSS THE WEST
CENTRAL/SOUTHWESTERN CWA BY THIS AFTERNOON. KEPT POPS SIMILAR TO THE
HIGH-RES MODEL OUTPUT THAT HAVE A GOOD HANDLE ON CURRENT CONDITIONS.

AS FOR TEMPERATURES HAVE WARMED EARLY MORNING TEMPERATURES AS WAA
AND CLOUD COVER HAS MOVED IN AND CONTINUE TO KEEP TEMPS FROM
DROPPING OFF TOO MUCH. SOME WAA TODAY...SO SHOULD SEE TEMPS WARMING
SOME EVEN WITH THE EXTENSIVE CLOUD COVER. HOWEVER STILL EXPECT
COOLER TEMPS ACROSS THE E/NE WITH THE WARMER AIR BISECTING THE CWA
FROM NW TO SE THROUGH THE DAY. THEREFORE HAVE MORE NEUTRAL TO CAA
ACROSS THE NORTHEAST.

.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 330 AM CST WED FEB 10 2016

THE PATTERN FROM WEDNESDAY NIGHT INTO FRIDAY IS QUITE SIMILAR TO
THAT BEING EXPERIENCED AT THE CURRENT TIME AND FORECAST FOR TODAY.
THAT IS...A SURFACE HIGH PRESSURE AREA WILL SLIDE ACROSS
NORTHEASTERN IOWA WHILE A BAND OF LIGHT SNOW MOVES OVERHEAD ON ITS
SOUTHWESTERN FLANK. ONCE AGAIN THE SNOW THAT FALLS ON
THURSDAY/THURSDAY NIGHT WILL ONLY AMOUNT TO AROUND AN INCH OR LESS
AND FALL WITH LIGHT WINDS...THE ONLY DIFFERENCE BEING THAT IT
SHOULD FALL A BIT FURTHER NORTHEAST THAN TODAYS SNOW.

ON FRIDAY A LARGE AND COLD AREA OF CANADIAN HIGH PRESSURE WILL
SURGE SOUTHWARD ACROSS THE MIDWESTERN REGION...SCOURING OUT THE
CLOUDS AND LIGHT SNOW AND BRINGING PLUMMETING TEMPERATURES AND
BRISK NORTHWEST WINDS BY FRIDAY NIGHT. AT DAYBREAK SATURDAY
MORNING THIS WILL RESULT IN WIND CHILLS IN THE 20 TO 30 BELOW ZERO
RANGE ACROSS NORTHERN IOWA AND HEADLINES ARE LIKELY.

THE 500 MB STEERING PATTERN ACROSS OUR REGION WILL FINALLY CHANGE
ON SATURDAY AS A LARGE AND PERSISTENT GYRE OVER THE EASTERN U.S.
WILL BE DISLODGED AND SHUNTED EASTWARD...CAUSING THE CYCLONIC FLOW
OVER IOWA TO GIVE WAY TO A SERIES OF LONGWAVE TROUGHS MOVING
THROUGH OTHERWISE WEST NORTHWEST OR NEARLY ZONAL FLOW. THE NET
RESULT OF THIS SHIFT WILL BE A MODERATION OF TEMPERATURES WITH
MONDAY HIGHS AROUND 25 DEGREES WARMER THAN SATURDAY HIGHS. IT WILL
ALSO RESULT IN A RETURN OF MORE ROBUST AND WIDESPREAD
SNOW CHANCES AROUND SATURDAY NIGHT OR POSSIBLY SUNDAY. THERE HAS
BEEN A PRETTY PERSISTENT SIGNAL FOR THIS SCENARIO FOR A FEW DAYS
NOW...BUT THE TIMING OF THE SNOW HAS BEEN ALL OVER THE PLACE. IN
ANY EVENT...THIS SYSTEM SHOULD HAVE SOMEWHAT BETTER MOISTURE AND
FORCING TO WORK WITH HOWEVER THE TROUGH WILL BE TRANSLATING
EASTWARD RATHER QUICKLY WHICH WILL LIMIT ACCUMULATIONS. AT THIS
POINT IT DOES NOT APPEAR PARTICULARLY HEAVY BUT WE WILL BE
MONITORING THE POTENTIAL THROUGHOUT THIS WEEK.

&&

.AVIATION...10/18Z
ISSUED AT 1127 AM CST WED FEB 10 2016

MVFR CIGS AND VIS WILL PERSIST THROUGH 20-22Z AS THE SNOW BAND IS
RAPIDLY DIMINISHING THIS AFTERNOON. VIS SHOULD IMPROVE WITH THE
LACK OF WIND AFTER THIS TIME FRAME. MVFR CIGS LOOK TO PERSIST OVER
DSM/FOD THROUGH THIS EVENING AS 925MB MOISTURE REMAINS IN PLACE.
FURTHER EAST AND NORTH...DRY AIR MAKES ITS WAY INTO NORTHEAST IOWA
AND LOOKS TO LIFT CIGS TO VFR.

&&

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

&&

$$

SHORT TERM...BEERENDS
LONG TERM...LEE
AVIATION...PODRAZIK



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