FXUS63 KDMX 050907
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
310 PM CST SUN FEB 5 2012

.SHORT TERM /TODAY/...
WIDESPREAD STRATUS FIELD CURRENTLY PUSHING SOUTH THOUGH NORTHERN IA
EARLY THIS MORNING AND REPRESENTS THE FORECAST CHALLENGE OF THE DAY.
THE STRATUS HAS BE SHIFTING SOUTH AT 16 KTS THE PAST FEW HOURS. THIS
WOULD BRING IT TO THE MISSOURI BORDER AROUND 16Z. THE HRRR HAS
INITIALIZED THE CLOUD PROGRESSION WELL AND SUGGESTS THEY WILL STICK
AROUND MOST OF THE DAY. IF ANY EROSION DOES OCCUR...IT WILL BE ON
THE OUTSIDE EDGES AND THIS WOULD LEAVE CENTRAL IA THE LAST TO
DISSIPATE. WITH NEW SNOW PACK OVER THE SOUTH...LIGHT WINDS AND LACK
OF STRONG SUBSIDENCE...FAVOR THE CLOUDY SOLUTION. THE LACK OF SUN
WILL RESULT IN BELOW GUIDANCE HIGHS TODAY. EXPECT SOME FOG EARLY IN
THE PERIOD AND THE POSSIBILITY REMAINS OF LOCALLY DENSE FOG. BEST
POTENTIAL WILL BE SOUTH OF HIGHWAY 30 AS THE HIGHER DEWPOINTS
ASSOCIATED WITH THE STRATUS SETTLES OVER THE NEW SNOW PACK WHERE
CONDITIONS HAVE ALREADY RADIATED.

.LONG TERM /TONIGHT THROUGH SATURDAY/...
OVERALL MID/LONG RANGE REMAINS RELATIVELY QUIET THROUGH THE
PERIOD...WITH MAINLY DRY CONDITIONS. ISSUE TONIGHT INTO
MONDAY...WILL BE IF STRATUS MOVING INTO THE CWA...WILL LINGER INTO
TONIGHT ACROSS THE AREA/BREAKUP/OR POSSIBLY EVEN REDEVELOP.
STRATUS/FOG HAS BEEN QUITE PERSISTENT ACROSS THE AREAS EAST OF THE
SFC HIGH PRES RIDGE SITUATED ACROSS THE CENTRAL DAKOTAS INTO NE/KS
THE PAST FEW DAYS...THEREFORE EXPECT THIS TREND TO CONTINUE TONIGHT.
THEREFORE HAVE INCREASED CLOUD COVER ACROSS THE SOUTHERN CWA
TONIGHT...AND ADDED IN A MENTION OF FOG AS HIGHER MOISTURE AIR
REMAINS IN PLACE OVER NEW SNOWPACK. OTHERWISE AS WINDS BECOME MORE
WESTERLY TO SOUTHWESTERLY AHEAD OF THE NEXT SYSTEM...EXPECT
CLOUDS/FOG TO ERODE ACROSS THE AREA MONDAY. TWO SYSTEMS OF NOTE
MONDAY INTO MONDAY NIGHT...WITH UPPER LEVEL SPLIT FLOW REGIME IN
PLACE. ONE STRENGTHENING UPPER LOW SITUATED ALONG THE FRONT RANGE OF
THE ROCKIES TUESDAY...EXPECTED TO SLIDE EAST INTO TUESDAY. ANOTHER
UPPER LEVEL SHORTWAVE DROPPING SOUTHEASTWARD FROM SASK/ALBERTA
THROUGH THE DAKOTAS/MN. THESE SYSTEMS TO MERGE OVER THE AREA TUESDAY
INTO TUESDAY NIGHT BRINGING INCREASING CLOUDS...AND POSSIBLY A
CHANCE FOR SOME LIGHT SNOW ACROSS THE SOUTHERN CWA. MAJORITY OF
PRECIPITATION EXPECTED TO FALL SOUTH OF IOWA...BUT SOUNDINGS TRY TO
SATURATE A BIT WITH WEAK LIFT ALONG AND SOUTH OF I-80. THEREFORE DID
EXPAND COVERAGE OF SLIGHT CHANCE POPS TO INCLUDE SOUTHERN HALF OF
CWA FOR TUESDAY...WITH THE SYSTEM QUICKLY SLIDING EAST/SOUTHEASTWARD
TUESDAY NIGHT WITH MAYBE SOME LINGERING SNOW ACROSS THE FAR
SOUTHEAST. OTHERWISE CAA EXPECTED THROUGHOUT THE DAY WITH
CLOUDS...SO EXPECT AN EARLY MAX TEMP WITH STEADY OR FALLING TEMPS
THROUGH THE REMAINDER OF THE DAY. HIGH PRESSURE TO BUILD INTO THE
AREA FOR WEDNESDAY...WITH BROAD UPPER LEVEL TROUGHING STILL EXPECTED
TO DIG SOUTHWARD ACROSS THE CENTRAL/EASTERN US FOR LATE IN THE WEEK.
THIS WILL BRING A COLD FROM SWEEPING THROUGH THE CWA
THURSDAY...SENDING H85 TEMPS INTO THE TEENS BELOW ZERO CELSIUS.
HOWEVER CANADIAN/GFS/PREVIOUS EC MUCH MORE AGGRESSIVE WITH THE SURGE
OF COLD AIR PLUNGING IT MUCH FURTHER SOUTH AND ALLOWING THIS ARCTIC
AIRMASS TO REMAIN IN PLACE ACROSS THE CWA FOR THE WEEKEND. LATEST
00Z EC IS MUCH DIFFERENT...KIND OF BRUSHING THE CWA WITH THE ARCTIC
AIRMASS AND THEN QUICKLY MODERATING THE TEMPS WITH WEAK UPPER
RIDGING INTO THE WEEKEND. THEREFORE SOME UNCERTAINTY WITH TEMPS
TOWARD THE END OF THE PERIOD...SO STUCK NEAR THE CONSALL GUIDANCE
GRIDS...WITH SOME TRENDING TOWARD THE COLDER SOLUTION DUE TO BETTER
CONTINUITY IN THE PAST FEW RUNS.

&&

.AVIATION...05/06Z
LARGE AREA OF STRATUS DROPPING SOUTH FROM MN NOW AND SOLID OVC003
WALL OF CLOUDS HEADING INTO THE AREA. ALREADY NEAR KMCW BY 06Z AND
EXPECTED TO HEAD TOWARD US 20 BY 08-09Z AT KALO AND KFOD. BY 12Z THE
AREA OF LOWER CLOUDS AND VSBY SHOULD BE NEARING KDSM AND THEN
BETWEEN 16-18Z FOR KOTM. WARM AIR ADVECTION ALOFT FROM THE NORTHERN
PLAINS AND SOUTHERN CANADA MAY ACT TO KEEP STRATUS GOING MOST OF THE
DAY ESPECIALLY GIVEN THE COLDER SFC TEMPS ACROSS MOST OF OUR AREA
NOW. WITH NEW SNOW PACK FROM I80 SOUTH TO BORDER...THIS AREA MIGHT
BE SUSCEPTIBLE TO THICK FOG DEVELOPMENT EITHER OVERNIGHT OR ON
SUNDAY AS WELL. NEXT FEW DAYS MAY THE REGION WILL HAVE ADDED
CHALLENGE OF BOUNDARY LAYER MOISTURE AND POSSIBLE ISSUES WITH FOG.
DIFFICULT TO TIME...BUT ONCE IT SETS UP...IT MAY STICK AROUND UNTIL
STRONGER SFC WINDS RETURN MONDAY NIGHT OR TUESDAY. HAVE PASSED
DETAILS ALONG TO NIGHT SHIFT FOR NEXT PACKAGE. /REV

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE

&&

$$

SHORT TERM...DONAVON
LONG TERM...BEERENDS
AVIATION...REV




















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