FXUS63 KGID 270422
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1022 PM CST THU NOV 26 2009
.AVIATION...06Z TAF. PER THE PREVIOUS DISCUSSION...VFR
CONDITIONS ARE FORECAST WITH NEARLY CLEAR SKIES...LIGHT
WINDS...AND NO VISIBILITY RESTRICTIONS.
&&
.PREV DISCUSSION... /ISSUED 515 PM CST THU NOV 26 2009/
AVIATION...00Z TAF. VFR CONDITIONS WILL OCCUR THROUGH THE
FORECAST PERIOD AS UPPER LEVEL HIGH PRESSURE PREVAILS. WINDS
WILL BE LIGHT WITH ONLY NEGLIGIBLE AMOUNTS OF CIRRUS LEVEL
CLOUDS EXPECTED.
PREV DISCUSSION... /ISSUED 336 PM CST THU NOV 26 2009/
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT. MILD AND TRANQUIL
WEATHER WILL PREVAIL THROUGH THE SHORT TERM PERIODS. AN UPPER LEVEL
RIDGE AXIS CURRENTLY OVER THE EASTERN ROCKIES/HIGH PLAINS WILL
EXPAND EAST ONTO THE CENTRAL PLAINS TONIGHT AND FRIDAY. WARM AIR
UNDER THE DOME OF HIGH PRESSURE WILL AVERAGE NEAR 16C AT H85
ALTHOUGH FORECAST SOUNDINGS SUGGEST MIXING WILL REACH CLOSER TO H9
ON FRIDAY. TEMPERATURES SHOULD CLIMB TO THE LOW TO MID 60S FOR
HIGHS AIDED BY A DOWN-SLOPE WIND COMPONENT AND ABUNDANT SUNSHINE.
FRIDAY WILL BE THE WARMEST DAY OF THE HOLIDAY WEEKEND AND THE
WARMEST BEFORE TEMPERATURES TURN MORE TOWARDS SEASONAL/WINTRY NEXT
WEEK. LOW TEMPERATURES BOTH TONIGHT AND FRIDAY WILL BE FAIRLY
SIMILAR IN THE MID/UPPER 20S TO THE LOWER 30S IN THE DRY AIRMASS.
LONG TERM...12Z SATURDAY THROUGH NEXT THURSDAY.
AS THE AREA HEADS INTO SATURDAY A POSITIVELY TILTED UPPER TROUGH
POSITIONED FROM THE NORTHERN HIGH PLAINS INTO THE DESERT SOUTHWEST
WILL DOMINATE THE PATTERN ACROSS THE CONUS AS ONLY A FLAT UPPER
RIDGE IS SEEN OVER THE EASTERN HALF OF THE COUNTRY. ALL MODELS POINT
TOWARD A MID TO UPPER LOW CLOSING OFF WITHIN THE TROUGH AXIS OVER
THE DESERT SOUTHWEST ON SATURDAY WHILE THE STRONGER WESTERLIES
CONTINUE TO SLIDE EAST ALONG THE CANADIAN BORDER. THE WILL PUSH A
COLD FRONT THROUGH THE AREA SATURDAY MORNING TO EARLY AFTERNOON
WHILE HIGH PRESSURE BUILDS INTO THE NORTHERN ROCKIES. DECENT CAA
BEHIND THIS BOUNDARY WILL PUSH 850MB TEMPERATURES INTO A +2C TO +7C
RANGE BY LATE AFTERNOON. GIVEN ADEQUATE MIXING...EXPECT THIS WILL
EQUATE TO HIGHS IN THE 50S.
SATURDAY NIGHT INTO SUNDAY WILL THEN TURN SLIGHTLY MORE ACTIVE AS
THE UPPER TROUGH AXIS SWINGS EAST THROUGH THE REGION. A WEAK
COUPLED JET STRUCTURE AHEAD OF THE TROUGH AXIS WILL PRODUCE SOME
MODEST LIFT/FRONTOGENESIS IN THE MID LEVELS LATE SATURDAY NIGHT INTO
SUNDAY MORNING AND SUSPECT THIS COULD PRODUCE SOME LIGHT SNOW
INITIALLY WEST OF AN ORD TO BEAVER CITY LINE BUT THEN MAINLY OVER
NORTH CENTRAL KANSAS ON SUNDAY.
MONDAY INTO TUESDAY THEN LOOK QUIET FOR THE AREA AS WEAK RIDGING
TAKES HOLD OF THE REGION AHEAD OF A STRONG CLIPPER SYSTEM DIGGING
INTO THE NORTHERN ROCKIES. THIS WILL ALLOW THE LEE TROUGH TO DEEPEN
OVER THE HIGH PLAINS WITH MODEST WAA TAKING CONTROL OF THE PLAINS IN
RESPONSE TO WINDS TURNING BACK TO THE SOUTH. WILL STAY ON THE
CONSERVATIVE SIDE TEMPERATURE WISE WITH HIGHS IN THE MID 40S TO
LOWER 50S BOTH DAYS...BUT TEMPERATURES COULD BE 5-8 DEGREES WARMER
THAN THESE VALUES ON TUESDAY.
THE MEDIUM RANGE MODELS CONTINUE TO POINT TOWARD A LARGE VORTEX
FORMING SOMEWHERE BETWEEN THE UPPER MIDWEST TO THE HUDSON BAY REGION
BY THE MIDDLE TO END OF NEXT WEEK. EACH MODEL SOLUTION HAS THIS
UPPER PATTERN PUSHING A MODIFIED ARCTIC FRONT THROUGH THE CENTRAL
PLAINS LATE TUESDAY NIGHT INTO EARLY ON WEDNESDAY. HOWEVER...TO
STATE THE OBVIOUS...THIS SPREAD IN THE UPPER VORTEX LOCATION
PRODUCES A WIDE SPREAD IN POSSIBLE OUTCOMES TEMPERATURE WISE AS THE
ECMWF IS MUCH COLDER THAN THE GFS WITH 850MB TEMPERATURES VARYING
FROM -4C IN THE GFS TO -12C IN THE ECMWF. CONFIDENCE IN ANY SOLUTION
AT THIS POINT IS LOW AND WILL AIM TOWARD SOMETHING IN THE MIDDLE FOR
NOW...BUT THIS WILL HAVE TO BE WATCHED VERY CLOSELY OVER THE NEXT
FEW DAYS AS TEMPERATURES COULD BE 10-15 DEGREES WARMER/COLDER THAN
VALUES FORECAST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
