FXUS63 KGLD 270536
AFDGLD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
1036 PM MST THU NOV 26 2009
.DISCUSSION...
215 PM MST THU NOV 26 2009
1730Z WATER VAPOR IMAGERY INDICATED LARGE UPPER LEVEL RIDGE ACROSS
THE WESTERN HALF OF THE CONUS. AT THE SFC...RIDGE AXIS WAS MOVING
OUT OF THE AREA WITH WEAK TROUGHING ACROSS EASTERN COLORADO. 12Z
OBSERVED SOUNDINGS INDICATED A MUCH WARMER AIRMASS IN PLACE AT DNR
THAN LBF OR DDC...WITH 800 MB TEMPS 9C WARMER AT DNR.
MAIN FORECAST CONCERNS FOR THE PERIOD WILL BE TEMPERATURES TOMORROW
FOLLOWED BY SNOW CHANCES ON SUNDAY.
TONIGHT...H5 RIDGE AXIS WILL SHIFT TO THE EAST OVERNIGHT AND BE
CENTERED OVER THE AREA...LEADING TO SUBSIDENCE...MAINLY CLEAR SKIES
AND DRY CONDITIONS. ONLY CONCERN FOR THE PERIOD WILL BE OVERNIGHT
TEMPERATURES...WHICH WILL BE A BATTLE BETWEEN WARMING TEMPERATURES
OVERNIGHT AND RADIATIONAL COOLING.
FRIDAY-FRIDAY NIGHT...H5 RIDGE WILL REMAIN DOMINANT FEATURE ACROSS
THE AREA THROUGH THE PERIOD. WEAK H5 TROUGH WILL LIFT NORTH INTO
SOUTHERN KANSAS...BUT WILL PRODUCE A LITTLE MORE THAN A FEW HIGH
CLOUDS. RIDGE WILL BEGIN TO BREAK DOWN AS COLD FRONT MOVES INTO THE
AREA OVERNIGHT. WITH AFOREMENTIONED WARM...DRY AND STABLE AIRMASS DO
NOT EXPECT ANY THREAT FOR PRECIP WITH FRONT. MODELS WOULD SUGGEST
THAT INVERSION WILL BE SO STRONG TOMORROW THAT ONLY A SHALLOW
BOUNDARY LAYER WILL DEVELOP. WITH CLEAR SKIES AND LIGHT WINDS...AM
NOT TOTALLY SOLD THAT DEEPER MIXING WILL NOT OCCUR. WITH TEMPS
ALREADY IN THE 60S TODAY...AND A SHARP INCREASE IN TEMPERATURES
ALOFT OVERNIGHT THINK TEMPERATURES SHOULD BE AT LEAST WARMER THAN
TODAY. CURRENT FORECAST LOOKS REASONABLE AND DID NOT MAKE ANY
CHANGES.
SATURDAY NIGHT-SUNDAY...H5 TROUGH AND ASSOCIATED COLD FRONT WILL
SWEEP ACROSS THE AREA EARLY SUNDAY MORNING. SHOULD SEE A PROLONGED
PERIOD OF FORCED ASCENT AS TROUGH SWEEPS ACROSS THE AREA. SOME LARGE
DIFFERENCES APPARENT BETWEEN THE GFS/NAM/ECMWF/CANADIAN WITH PRECIP
AMOUNTS AND GENERAL STRENGTH OF THE FORCING. ALTHOUGH THERE IS SOME
UNCERTAINTY TO AMOUNTS...EVEN WEAKER MODELS LIKE GFS SUGGEST
POSSIBILITY OF A MODERATELY STRONG FRONTAL BAND SWEEPING ACROSS THE
AREA ON SUNDAY. FORCING APPEARS TO BE CENTERED AROUND 650 MB. WITH
POCKET OF WEAKLY STABLE TO NEGATIVE EPV* ABOVE FRONTAL ZONE...IT
WOULD NOT BE UNREASONABLE TO SEE A STRONG RESPONSE TO EVEN THE
WEAKER FORCING. GIVEN THE UNCERTAINTY AND TRANSIENT NATURE OF THE
SYSTEM...THINK AMOUNTS WILL GENERALLY BE 2 INCHES OR LESS.
IN THE EXTENDED...MEDIUM RANGE MODELS HAVE COME IN TO BETTER
AGREEMENT WITH HANDLING OF TROUGH DURING THE BEGINNING OF THE
WEEK...WITH ANY LIGHT PRECIPITATION LIKELY ON THE DECLINE BY SUNDAY
EVENING. SHORTWAVE RIDGING WILL BUILD OVER THE AREA MONDAY AND
TUESDAY LEADING TO A BRIEF WARM UP PRIOR TO THE NEXT STRONG COLD
FRONT ON WEDNESDAY. WHILE ENSEMBLES SUGGEST A VARY WIDE SPREAD OF
TEMPERATURES BEHIND THE FRONT WHICH HAS BEEN SHOWN BY VARIOUS RUN TO
RUN DIFFERENCES...00/06 OPERATIONAL RUNS AND A FAIR AMOUNT OF
INDIVIDUAL ENSEMBLE MEMBERS OF CANADIAN AND GFS SUPPORT A SOLUTION
THAT BRINGS MUCH COLDER AIRMASS INTO THE AREA. WHILE THESE SOLUTIONS
COULD SUPPORT THE POSSIBILITY OF AN ARCTIC AIRMASS WHERE HIGHS WOULD
STRUGGLE TO REACH THE 20S...THERE IS ENOUGH UNCERTAINTY TO NOT
TOTALLY GO THAT ROUTE BUT WILL DEFINITELY TREND COLDER.
JRM
&&
.AVIATION...
1031 PM MST THU NOV 26 2009
FOR THE 06Z TAF...WITH HIGH PRESSURE FIRMLY IN PLACE OVER THE
CENTRAL HIGH PLAINS... VFR CONDITIONS WILL CONTINUE TO PREVAIL AT
BOTH KMCK AND KGLD THROUGH THE NEXT 24 HOURS. SOUTHWESTERLY WINDS
WILL EVENTUALLY BECOME LIGHT AND VARIABLE AFTER 19Z AT KGLD.
EXPECT MINIMAL SKY COVER THROUGH THE TAF PERIOD WITH PERHAPS A BIT
OF THIN CIRRUS FROM TIME TO TIME.
FOLTZ
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$