Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 222033
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
333 PM CDT SUN MAR 22 2015

.SHORT TERM /TONIGHT/...
ISSUED AT 333 PM CDT SUN MAR 22 2015

LOW PRESSURE OVER NORTHWEST KANSAS EXTENDS AN INVERTED TROUGH
NORTHEAST INTO EASTERN SOUTH DAKOTA.  LOW WILL CONTINUE SOUTHEAST
TONIGHT WITH INVERTED TROUGH WEAKENING WITH TIME.  MODELS SHOW
STRONG FORCING INT HE 850 TO 800 MB LAYER.  BEST SUPPORT WILL BE
THIS EVENING TO THE NORTHEAST OF THE CWA.  SOME INSTABILITY
ASSOCIATED WITH THIS SYSTEM.  THIS CAN BE SEEN IN THE RADAR JUST
WEST OF THE COLD FRONT. NMM MODELS AVE A PRETTY GOOD HANDLE ON
THIS AND WILL GO WITH THAT TIMING FOR THE PRECIP OUTSIDE OF THE
BANDED ARE. AS FOR ACCUMULATION...FEEL ACCUMULATION WILL BE
LIMITED TO MY FAR NORTHEAST PART OF THE CWA AND UNDER AN INCH.

.LONG TERM /MONDAY THROUGH SUNDAY/...
ISSUED AT 333 PM CDT SUN MAR 22 2015

SOME LIGHT LINGERING PRECIPITATION FROM THE SYSTEM CURRENTLY PUSHING
THROUGH THE CWA SHOULD JUST BE EXITING THE CWA EARLY MONDAY...WITH
HIGH PRESSURE BUILDING INTO THE CWA BRIEFLY. MODELS INDICATE LOW
LEVEL STRATUS REMAINING ACROSS MUCH OF THE CWA MONDAY...WITH SOME OF
THE CLOUD DECK ERODING ACROSS THE FAR WEST/NORTHWEST THROUGH THE
DAY. ANY BREAKS IN THE CLOUDS ARE QUICKLY FILLED IN WITH CLOUDS
MOVING IN AHEAD OF THE NEXT SYSTEM FOR LATE MONDAY NIGHT INTO
TUESDAY NIGHT. NAM MOST BULLISH WITH THIS NEXT SYSTEM...AND APPEARS
TO BE OVERDONE AND TOO PROGRESSIVE AND OVERALL AN OUTLIER. WITH IT
TRYING TO MOVE PRECIPITATION IN FASTER...SUGGESTS INITIAL PRECIP
WOULD FALL AS FREEZING RAIN OR MIX WITH SNOW. GIVEN THE AMOUNT OF
DRY AIR TO INITIALLY OVERCOME AND EASTERLY SURFACE FLOW...HISTORICAL
TRENDS WITH THIS TYPE OF SYSTEM SUGGESTS A LATER ONSET OF PRECIP SO
TRENDED TOWARD THE SLOW SOLUTIONS WHICH KEEPS THE MAJORITY OF PRECIP
LINING UP WITH THE WARMER AIR MOVING IN ALOFT WHICH SHOULD KEEP ALL
THE PRECIP RAIN WITH SFC TEMPS WARMING ABOVE FREEZING PRIOR TO THE
PRECIP ONSET. TRACK OF THE SURFACE LOW IS A BIT FURTHER SOUTH ALONG
WITH THE PLACEMENT OF THE UPPER LOW...THEREFORE AMOUNT OF WARMING IS
TEMPERED SOME AND ELEVATED INSTABILITY IS LIMITED. HAVE THUS REMOVED
MUCH OF THE THUNDER WORDING ACROSS THE CWA...CONFINING IT TO MAINLY
TUESDAY AFTERNOON INTO TUESDAY EVENING ACROSS THE FAR SOUTH WHEN
LAPSE RATES LOOK STEEPER THE WARM FRONT ALOFT MOVES INTO THE AREA.

OVERALL EXPECT A BAND/AREA OF RAIN SHOWERS TO SPREAD NORTH ACROSS
THE SOUTHERN CWA LATE MONDAY NIGHT...AND MOVE NORTH/NORTHEASTWARD
THROUGH CENTRAL AND NORTHERN PORTIONS OF THE CWA TUESDAY MORNING.
THESE TYPES OF SCENARIOS MODELS TEND TO OVERDO THE DURATION OF
PRECIPITATION SO DO EXPECT A DRY PERIOD AFTER THE INITIAL AREA OF WAA
PRECIP PUSHES THROUGH BEFORE PRECIP REDEVELOPMENT EXPECTED IN
VICINITY OF THE INVERTED SFC TROUGH EXPECTED TO SWING THROUGH THE
SOUTHERN CWA TUESDAY AFTERNOON. WRAP-AROUND PRECIP  ON THE BACKSIDE
OF THE SYSTEM EXPECTED TO SWING THROUGH THE CENTRAL/NORTH TUESDAY
AFTERNOON INTO TUESDAY NIGHT AS THE UPPER SYSTEM LIFTS INTO THE
GREAT LAKES BY EARLY WEDNESDAY. THERMAL PROFILES SUGGEST SOME SNOW
COLD MIX IN WITH THE RAIN TUESDAY NIGHT ACROSS THE FAR NORTH...WITH
BETTER CHANCES FOR WINTRY PRECIP INTO MINNESOTA. SECONDARY SYSTEM
STILL EXPECTED TO DIG INTO THE BACKSIDE OF THIS WAVE WEDNESDAY INTO
THURSDAY...SHOULD KEEP OVERALL CLOUDINESS ACROSS THE REGION WITH ANY
PRECIP REMAINING JUST TO THE NORTH/EAST OF THE CWA.

MUCH COLDER AIR TO SINK INTO THE STATE BEHIND THIS SYSTEM INTO
FRIDAY...WITH A LARGE 1036 MB ARCTIC HIGH BUILDING IN WITH H85 TEMPS
DROPPING INTO THE -15C RANGE BY THE END OF THE WEEK. THIS WILL ALLOW
FOR CHILLY CONDITIONS TO RETURN TO THE CWA BY FRIDAY...WITH UPPER
LEVEL RIDGING BUILDING BACK IN FOR THE WEEKEND AND TEMPS WARMING
BACK TOWARD THE SEASONAL AVERAGES OF ABOVE BY THE END OF THE
UPCOMING WEEKEND. QPF AMOUNTS FOR THE EARLY WEEK SYSTEM SHOULD BRING
A WIDESPREAD HALF INCH TO THREE-QUARTERS OF AN INCH OF RAIN...AND
POSSIBLY AS MUCH AS AN INCH OF RAIN OR MORE IN LOCATIONS THAT MAY
SEE AN ISOLATED THUNDERSTORM.

&&

.AVIATION...22/18Z
ISSUED AT 1234 PM CDT SUN MAR 22 2015

LOW PRESSURE OVER SOUTH CENTRAL NEBRASKA WILL MOVE SOUTHEAST
ACROSS MISSOURI TONIGHT. MIXED PRECIPITATION WILL OCCUR TONIGHT
OVER THE NORTHEAST SITES...WITH SCATTED SHOWERS OVER THE
SOUTHWEST. FOLLOWING LOW PASSAGE MVFR CIGS ARE EXPECTED OVERNIGHT
INTO MONDAY. IMPROVING CONDITIONS MONDAY AFTERNOON AND NIGHT.

OUTLOOK...NEXT WEATHER SYSTEM WILL MOVE INTO THE CENTRAL U.S.
LATE TUESDAY NIGHT INTO WEDNESDAY NIGHT. EXPECT WIDESPREAD MVFR TO
IFR CONDITIONS.


&&

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

&&

$$

SHORT TERM...MS
LONG TERM...BEERENDS
AVIATION...MS MAR 15



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