FXUS63 KGID 081723
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1123 AM CST TUE DEC 8 2009
.AVIATION...18Z TAF. SNOW WILL CONTINUE AT KGRI THROUGH THE
AFTERNOON HOURS. THE SNOW COULD BE HEAVY AT TIMES...AND EXPECT
VISIBILITIES TO REMAIN AT 1/2SM OR BELOW MUCH OF THE AFTERNOON.
THE SNOW WILL GRADUALLY END THIS EVENING...BUT WITH WINDS
INCREASING HAVE KEPT REDUCED VISIBILITIES DUE TO BLOWING SNOW. ITS
HARD TO SAY WHEN THE BLOWING SNOW WILL DIMINISH...BUT WINDS SHOULD
BEGIN TO SUBSIDE SOME LATE TONIGHT...SO WILL TRY TO IMPROVE THEM
DURING THE LATE NIGHT HOURS.
&&
.PREV DISCUSSION... /ISSUED 303 AM CST TUE DEC 8 2009/
DISCUSSION...SNOW AND MORE SNOW TODAY...WITH BLOWING SNOW ISSUES
AND DANGEROUS WIND CHILLS TONIGHT. SNOW HAS BEEN ONGOING FOR
SEVERAL HOURS ACROSS OUR CWA WITH NEW SNOWFALL AMOUNTS HAVE GENERALLY
BEEN LIGHT IN THE HALF INCH TO AROUND AN INCH RANGE. THE COVERAGE
OF SNOW WITH SOME ENHANCED BANDS HAS BEGUN TO INCREASE DURING THE
LAST HOUR WHICH FITS WELL AS MODELS INDICATE THIS SHOULD OCCUR
BETWEEN 09-12Z. MODELS ARE STILL IN GOOD AGREEMENT WITH THE MID
LEVEL CIRCULATION CLOSING OFF ACROSS COLORADO THIS MORNING WITH
THE TRACK OF THE H7 PROGRESSING EAST THRU NORTHERN KS TODAY THEN
THE SYSTEM DEPARTS INTO SOUTHERN WISCONSIN TONIGHT. OF INTEREST IS
THE RUC IS DEEPER WITH THE SYSTEM ACROSS COLORADO MIDDAY THAN THE
OTHER MODELS AND THE GFS IS SLIGHTLY FARTHER SOUTH WITH THE H7 LOW
AND FASTER WITH THE SYSTEM THAN THE NAM/ECMWF. THE GFS TRACK PLACES THE
HEAVIER SNOWBAND SOUTHEAST OF WHERE WE HAD IT YESTERDAY BUT THE
NAM/ECMWF ARE FAIRLY SIMILAR WITH POSITION BUT HAVE BACKED OFF
SLIGHTLY ON AMOUNTS. OVERALL THE DIFFERENCES JUST AMOUNT TO A
COUPLE OR FEW INCHES OF SNOW DISPLACED NORTH OR SOUTH AND OPTED TO
JUST TWEAK THE SNOWFALL TOTALS. WE ARE STILL LOOKING AT WIDESPREAD
AND SIGNIFICANT SNOW ACCUMULATIONS FROM 6-14 INCHES OVERALL NW/SE.
ISENTROPIC LIFT ON THE 290K SURFACE REALLY GETS GOING BY 12Z AHEAD
OF THE DEEPENING LOW IN COLORADO AND LIFT/DYNAMICS CONTINUE ALL DAY
AS THE SYSTEM TRACKS ACROSS THE PLAINS. A SOLID 12 HOURS OF
MODERATE TO HEAVY SNOWFALL IS EXPECTED TODAY BEFORE THE SNOW BEGINS
TO TAPER OFF THIS EVENING/TONIGHT. SNOW RATIOS RANGE FROM ROUGHLY
12:1 TO 20:1 AND HAVE WENT WITH AN AVERAGE OF 15:1 FOR THE EVENT BUT
THIS COULD BE MORE ON THE ORDER OF 18:1 AT TIMES.
THE SURFACE LOW DEEPENS TODAY AND WINDS SHIFT NORTH AND INCREASE
BEHIND THE LOW THIS AFTERNOON. WINDS WILL INCREASE TO 25 TO 30 MPH
AND GUST NEAR 40 MPH IN THE TIGHT PRESSURE GRADIENT AND THIS WILL
CAUSE WIDESPREAD BLOWING AND DRIFTING SNOW AND LOW VISIBILITIES.
TEMPERATURES TONIGHT WILL DROP TO THE SINGLE DIGITS BOTH ABOVE AND
BELOW ZERO AND WHEN COMBINED WITH THE WIND...WIND CHILL READINGS
WILL BE IN THE 15 TO 25 DEGREE BELOW RANGE. THE WINDS REMAIN BREEZY
WEDNESDAY MORNING...IN THE 15 TO 25 MPH RANGE AND BLOWING AND
DRIFTING OF THE NEWLY FALLEN SNOW WILL CONTINUE TO BE AN ISSUE. THE
CURRENT WINTER STORM WARNING HEADLINE IN EFFECT THROUGH TONIGHT
COVERS THE MULTIPLE HEADLINES WELL. NEAR BLIZZARD CONDITIONS MAY
OCCUR WITH THE INCREASE IN WINDS...BUT THE HEAVIER SNOW SHOULD BE
WINDING DOWN AS THE STRONGEST WINDS ARRIVE. NEXT SHIFT CAN EVALUATE
TRENDS TO SEE IF A HEADLINE UPGRADE IS NEEDED.
ARCTIC HIGH PRESSURE SETTLES ACROSS THE HIGH PLAINS ON WEDNESDAY AND
TEMPERATURES WILL STRUGGLE IN THE ARCTIC AIRMASS ESPECIALLY WITH THE
FRESH SNOW COVER. HAVE ONLY PLACED HIGHS IN THE SINGLE DIGITS ABOVE
ZERO AND WE'LL SEE IF WE CAN MANAGE THAT. SUB ZERO LOWS ARE
EXPECTED AGAIN WEDNESDAY NIGHT THEN HEIGHTS BEGIN TO RISE THURSDAY
AND THE AIRMASS MODERATES ABOUT 5C AND WE MAY ACTUALLY REACH THE
TEENS IN THE AFTN.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER STORM WARNING UNTIL 6 AM CST WEDNESDAY FOR NEZ039>041-
046>049-060>064-072>077-082>087.
KS...WINTER STORM WARNING UNTIL 6 AM CST WEDNESDAY FOR KSZ005>007-
017>019.
&&
$$
