FXUS63 KGID 251121
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
521 AM CST WED NOV 25 2009
.AVIATION...12Z TAF. A FAST MOVING UPPER LEVEL DISTURBANCE BROUGHT
LIGHT RAIN TO SOUTH CENTRAL NEBRASKA. THIS WILL CONTINUE TO MOVE
QUICKLY SOUTHEAST...AND THINK THAT KGRI SHOULD PROBABLY BE DRY
NEAR 12Z. A FEW MVFR CEILINGS HAVE ALSO ACCOMPANIED THE LIGHT RAIN
THIS MORNING...BUT THEY APPEAR TO EXIT QUICKLY WITH THE
PRECIPITATION. TIME CROSS SECTIONS OF RELATIVE HUMIDITY SHOWS THE
POSSIBILITY OF CEILINGS AROUND 6-8KFT LINGERING FOR A FEW HOURS
THIS MORNING...BUT THEY SHOULD SCATTER OUT BY LATE MORNING. WINDS
WILL QUICKLY INCREASE THIS MORNING WITH GUSTS OF 30 TO 35 KTS
POSSIBLE BY MID MORNING. WINDS WILL THEN DECREASE QUICKLY TOWARDS
SUNSET.
&&
.PREV DISCUSSION... /ISSUED 418 AM CST WED NOV 25 2009/
DISCUSSION...MAIN FOCUS IS ON LIGHT PRECIP THIS MORNING AND WIND
SPEEDS TODAY.
EARLY MORNING WATER VAPOR IMAGERY SHOWED AN ACTIVE NORTHWEST FLOW
ALOFT PREVAILING OVER THE CENTRAL CONUS. THE UPPER LOW THAT BROUGHT
RAIN TO THE AREA MONDAY NIGHT WAS CHURNING THROUGH NORTHERN
IL/SOUTHERN WI...WITH A TRAILING SHORTWAVE DIVING SOUTHEAST THROUGH
THE NORTHERN PLAINS. LAST EVENING UPPER AIR OBS ALONG WITH LATEST
RUC ANALYSIS DATA REVEAL A 110 KT H3 JET STREAK NOSING INTO
NORTHWEST NE. THE MID/UPPER LEVEL SHORTWAVE WAS PUSHING A COLD FRONT
SOUTH THROUGH THE NORTHERN AND CENTRAL PLAINS STATES...WHICH IS
PLOWING THROUGH THE CENTRAL CWA ATTM. COMBINATION OF FORCING FROM
SHORTWAVE AND UPPER JET STREAK ALONG WITH FRONTAL FORCING HAS
GENERATED AN AREA OF LIGHT PRECIPITATION WORKING SOUTH THROUGH NE
EARLY THIS MORNING. THIS FAIRLY STRONG FORCING HAS OVERCOME DRY AIR
IN THE LOW LEVELS TO PRODUCE SOME MEASURABLE PRECIPITATION. UPSTREAM
SITES INCLUDING KODX AND KBBW HAVE CLICKED OFF A HUNDREDTH OR
TWO...AND AREA WEBCAMS AND A PEEK OUTSIDE DEFINITELY CONFIRM MORE
THAN JUST SPRINKLES/FLURRIES. THUS HAVE INCREASED POPS FOR THE EARLY
MORNING HOURS. THE PRECIP HAS BEEN MAINLY IN THE FORM OF RAIN AS
GUSTY WINDS BEHIND THE FRONT ARE MIXING DOWN WARMER AIR FROM
ALOFT...CAUSING SURFACE TEMPS TO SPIKE INTO THE MID 30S TO LOWER
40S.
THE COLD FRONT WILL CONTINUE TO PUSH RAPIDLY SOUTH THROUGH THE
CWA EARLY THIS MORNING...AIDED BY 3-HR PRESSURE RISES OF 3-4 MB
BEHIND IT PER MSAS DATA. THE SWATH OF LIGHT PRECIP WILL ALSO
CONTINUE TO ADVANCE SOUTHWARD...AND SHOULD CLEAR THE SOUTHERN CWA BY
MID TO LATE MORNING. ATTENTION THEN TURNS TO INCREASING NORTHWEST
WINDS BEHIND THE FRONTAL BOUNDARY. TIGHTENED PRESSURE
GRADIENT...DEEP MIXING TO 775-800MB...AND SUBSIDENCE BEHIND
SHORTWAVE ALL POINT TO A WINDY DAY. WILL LIKELY BE VERY CLOSE TO
WIND ADVISORY CRITERIA AT TIMES FROM AROUND MIDDAY INTO MID AFTERNOON
ESPECIALLY IN THE NORTH/NORTHEAST CWA WHERE THE GRADIENT WILL BE
TIGHTER. DEBATED A WIND ADVISORY BUT DECIDED TO HOLD OFF FOR NOW
AS IT STILL LOOKS MARGINAL...BUT WOULDN/T BE SURPRISED TO SEE A
SITE OR TWO BRIEFLY TOUCH CRITERIA EARLY THIS AFTERNOON. WILL
MENTION IN THE HWO...AND DAY SHIFT WILL HAVE TO MONITOR TRENDS
THIS MORNING. ONE ENCOURAGING SIGN IS THAT THE 06Z NAM IS NOT
MIXING AS DEEP AS THE 00Z RUN...WHICH COULD HOLD SPEEDS DOWN JUST
A TOUCH. AGAIN...THE STRONGEST WINDS SHOULD BE FROM AROUND MIDDAY
INTO MID AFTERNOON...AND THEN START TO WEAKEN BY LATE AFTERNOON AS
THE PRESSURE GRADIENT WEAKENS. MIXING TO AROUND 800MB YIELDS HIGHS
IN THE LOWER 40S NORTH TO UPPER 40S SOUTH...BUT STRONG WINDS WILL
MAKE IT FEEL MUCH COOLER THAN THIS. WILL SEE SOME PRETTY QUICK
CLEARING LATER THIS MORNING INTO THE AFTERNOON THANKS TO STRONG
SUBSIDENCE BEHIND SHORTWAVE.
FAIRLY TRANQUIL CONDITIONS ARE THEN EXPECTED TONIGHT THROUGH FRIDAY.
A NORTH TO NORTHWEST FLOW ALOFT WILL PREVAIL TONIGHT IN BETWEEN THE
EXITING UPPER WAVE AND RIDGING OVER THE WESTERN CONUS. MOSTLY CLEAR
SKIES...LIGHT WINDS...AND A DRY AIRMASS WILL SET THE STAGE FOR GOOD
RADIATIONAL COOLING...ALLOWING LOWS TO FALL INTO THE UPPER TEENS TO
MID 20S. TEMPERATURES WILL BEGIN A SOLID REBOUND ON THANKSGIVING AS
THE UPPER RIDGE BEGINS TO SHIFT EASTWARD AND WEST TO SOUTHWEST
SURFACE WINDS PREVAIL. WILL BE A PLEASANT DAY WITH HIGHS IN THE
UPPER 40S TO UPPER 50S...LIGHT BREEZES...AND PLENTY OF SUN. THE
UPPER RIDGE SHIFTS EAST OVER THE PLAINS ON FRIDAY. 850MB TEMPS CLIMB
TO 11-14C PER WAA. MIXING WON/T BE QUITE TO THIS LEVEL...MORE LIKE
900 OR MAYBE 875MB...WHICH STILL POINTS TO HIGHS IN THE UPPER 50S TO
LOWER 60S.
NO SIGNIFICANT CHANGES MADE TO THE WEEKEND AND BEYOND. A COLD FRONT
WILL PUSH THROUGH SATURDAY...DROPPING TEMPS BACK BUT NO PRECIP IS
EXPECTED WITH THE FRONT. THE NEXT UPPER TROUGH WILL COME INTO
PLAY LATE IN THE WEEKEND INTO EARLY NEXT WEEK. STILL SOME
DIFFERENCES TO BE RESOLVED WITH THIS SYSTEM...BUT MOST OF THE PRECIP
TIED TO SOUTHERN STREAM ENERGY LOOKS TO STAY MAINLY SOUTH OF THE
AREA AT THIS POINT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
