Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 080528
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1128 PM CST SUN FEB 7 2016

.UPDATE...
ISSUED AT 1120 PM CST SUN FEB 7 2016

HAVE ISSUED A WINTER WEATHER ADVISORY FOR SOUTHWEST IOWA AND FAR
EASTERN NEBRASKA AS VISIBILITIES HAVE DROPPED TO A MILE OR LESS IN
SOME OF THE SNOW SHOWERS MOVING THROUGH THE REGION LATE THIS
EVENING. UPSTREAM SNOWS LOOK LESS WIDESPREAD...BUT WITH ANY
SNOWFALL WHEN COMBINED WITH WINDS GUSTING TO 40 MPH...REDUCED
VISIBILITIES ARE LIKELY...ESPECIALLY IN OPEN AREAS. SEVERAL
IMPULSES ROTATING THROUGH NORTHWEST FLOW ALOFT WILL LIKELY TOUCH
OFF SNOW SHOWERS THROUGH MID MORNING. STEEP LOW LEVEL LAPSE RATES
AND A GOOD 7000FT LAYER OF SATURATED DENDRITIC TEMPERATURES WILL
PROVIDE A BACKDROP FOR EFFICIENT SNOW PRODUCTION. AMOUNTS SHOULD
AMOUNT TO ONLY A FEW TENTHS HOWEVER. BUT EVEN WHEN THE SNOW IS NOT
FALLING...WILL STILL SEE AT LEAST ADVISORY LEVEL WINDS.

&&

.SHORT TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 250 PM CST SUN FEB 7 2016

WINDS AND SNOW SHOWERS WILL CONTINUE TO PROVIDE THE PRIMARY FORECAST
CHALLENGES THROUGH MONDAY.

100+ KNOT 300 MB WINDS EXTENDED FROM NORTHEAST BRITISH COLUMBIA DOWN
INTO WYOMING AT 12Z ON THE BACKSIDE OF A DIGGING MID TROPOSPHERIC
TROUGH. AT 500 MB...12 HOUR HEIGHT FALLS OF UP TO 160 METERS WERE
NOTED FROM MINNESOTA INTO SOUTHEAST SOUTH DAKOTA...WITH 500 MB
TEMPERATURES OF -30 C OR COLDER. MODEST COLD AIR ADVECTION WAS
NOTED AT BOTH 700 MB AND 850 MB FROM OUR AREA NORTHWEST INTO THE
WESTERN DAKOTAS AND EASTERN MONTANA. SURFACE ANALYSIS AT 19Z HAD
A LOW PRESSURE CENTER OVER THE FAR NORTHEAST TIP OF MINNESOTA AND
STRONG NORTHWEST FLOW FROM THE DAKOTAS DOWN INTO NEBRASKA. THE
ATMOSPHERE WAS WELL MIXED WITH TEMPERATURES MAINLY IN THE 30S TO
MID 40S. STRONGEST WINDS NOTED SO FAR HAVE MOSTLY BEEN IN WESTERN
SOUTH DAKOTA.

SHOWERS...MAINLY SNOW SHOWERS...HAVE BEEN MOVING DOWN FROM PARTS
OF NORTHEAST NEBRASKA INTO EAST CENTRAL NEBRASKA AND WESTERN
IOWA. THESE COULD PRODUCE SNOW AMOUNTS UP TO AROUND HALF AN INCH
OR LOCALLY MORE BUT WOULD BE FAIRLY SCATTERED. FORECAST SOUNDINGS
CONTINUE TO SHOW FAIRLY STEEP LAPSE RATES BELOW 700 MB AND EVEN
SOME VERY LOW CAPE VALUES...THUS THE CONVECTIVE/SHOWERY NATURE OF
THE SNOW SHOULD CONTINUE AT LEAST THIS EVENING AND PROBABLY FOR
PART OF THE OVERNIGHT.

DECIDED TO EXTEND THE CURRENT WIND ADVISORY FOR ABOUT THE
NORTHWEST HALF OF THE FORECAST AREA UNTIL NOON MONDAY. FARTHER
SOUTH...WE STARTED A WIND ADVISORY STARTING LATER TONIGHT AND
WILL RUN THAT UNTIL LATE MONDAY AFTERNOON. THIS MAY NEED SOME
ADJUSTMENT THIS EVENING IF STRONG WINDS PUSH FARTHER TO THE
SOUTHEAST FASTER.

REGARDING THE BLOWING AND DRIFTING SNOW...THERE WILL BE SOME...
ESPECIALLY DRIFTING SNOW. AT LEAST FOR NOW...DECIDED TO HANDLE
THAT WITH SPS PRODUCTS. WEB CAMS AND REPORTS UP TO THIS POINT
INDICATE THAT THE SNOW IS MAINLY DRIFTING...AND NOT BEING LOFTED
HIGH ENOUGH TO CAUSE SIGNIFICANT OR WIDESPREAD REDUCTIONS TO
VISIBILITY. WILL STILL MENTION SOME BLOWING SNOW IN OUR PRODUCTS
THOUGH.

WINDS WILL SLOWLY DECREASE WITH SNOW CHANCES DROPPING THROUGH
THE DAY MONDAY AS WELL AS LOW PRESSURE MOVES SOUTHEAST AND OUR
PRESSURE GRADIENT DECREASES. TEMPERATURES ARE NOT EXPECTED TO
RECOVER MUCH...WITH HIGHS IN THE RANGING FROM THE MID 20S TO
LOWER 30S.

NO PCPN IS EXPECTED MONDAY NIGHT...BUT WE COULD SEE SOME LIGHT
SNOW TRY TO MOVE IN FROM THE NORTHWEST LATE TUESDAY OR TUESDAY
NIGHT. AT THIS TIME...DECIDED TO KEEP MENTION OF LIGHT SNOW OUT
OF THE FORECAST FOR THOSE PERIODS WITH BETTER FORCING STAYING TO
OUR WEST.

HIGH TEMPS TUESDAY AND WEDNESDAY SHOULD RANGE FROM 30S IN SOME
OF OUR WESTERN AND SOUTHERN ZONES TO 20S IN THE NORTHEAST PART OF
THE FORECAST AREA.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 250 PM CST SUN FEB 7 2016

PATTERN LOOKS SIMILAR TO WHAT IS HAS THE PAST FEW DAYS. A MID
LEVEL RIDGE WILL BE OVER THE WESTERN UNITED STATES AND WESTERN
CANADA AT THE START OF THIS PERIOD...WITH A TROUGH FROM HUDSON
BAY DOWN INTO THE MID ATLANTIC. THAT RIDGE WILL BUILD SLOWLY
EASTWARD WITH TIME...BUT REMAIN TO OUR WEST UNTIL SATURDAY. THE
OVERALL FLOW SHOULD BECOME LESS MERIDIONAL FROM WEDNESDAY TO
FRIDAY.

MODELS SHOW SOME SMALL CHANCES FOR PCPN...BUT IN GENERAL DO NOT
AGREE ON TIMING OR LOCATIONS. WILL HOLD POPS BELOW 15 PERCENT FOR
NOW AND ADJUST WITH LATER FORECASTS. HIGHS IN THIS PERIOD WILL
LIKELY REMAIN IN THE 20S OR 30S...DEPENDING ON IF ANY LOW LEVEL
COLD AIR INTRUSIONS CAN PUSH IN FROM THE NORTH/NORTHEAST. AT
LEAST FOR NOW...EXPECT SOME MODERATION BY SUNDAY.

&&

.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1120 PM CST SUN FEB 7 2016

NORTH TO NORTHWEST WINDS IN THE 25 TO 40KT RANGE WILL PERSIST AT
ALL TAF SITES THROUGH MONDAY AFTERNOON BEFORE BEGINNING TO SUBSIDE
AFTER 00Z. SCATTERED SNOW SHOWERS WILL LIKELY AFFECT KOMA THROUGH
MID MORNING...OCCASIONALLY DROPPING CIGS/VSBYS TO MVFR...WITH
BRIEF IFR CONDITIONS POSSIBLE. KOFK AND KLNK SHOULD REMAIN WEST OF
THE BEST SNOW SHOWER POTENTIAL...WITH GENERALLY VFR CIGS EXPECTED
AT THOSE SITES.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 9 AM CST MONDAY FOR NEZ015-034-045-
     052-053-067-068.

     WIND ADVISORY FROM 9 AM TO 5 PM CST MONDAY FOR NEZ045-052-053-
     067-068.

     WIND ADVISORY FROM 3 AM TO 5 PM CST MONDAY FOR NEZ051-065-066-
     078-088>093.

     WIND ADVISORY UNTIL NOON CST MONDAY FOR NEZ011-012-016>018-
     030>033-042>044-050.

     WIND ADVISORY FROM 9 AM TO NOON CST MONDAY FOR NEZ015-034.

IA...WINTER WEATHER ADVISORY UNTIL 9 AM CST MONDAY FOR IAZ043-055-056-
     069-079-080-090-091.

     WIND ADVISORY FROM 9 AM TO 5 PM CST MONDAY FOR IAZ055-056-069-
     079-080-090-091.

     WIND ADVISORY FROM 9 AM TO NOON CST MONDAY FOR IAZ043.

&&

$$

UPDATE...DERGAN
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...DERGAN


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