Monday, October 25, 2010

Area Forecast Discussion - South Central/Southwest Missouri

FXUS63 KSGF 251123
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
623 AM CDT MON OCT 25 2010

..UPDATE TO AVIATION...

DISCUSSION...

PESKY UPPER LOW HAS FINALLY EXISTED TO OUR EAST THIS MORNING...WITH
SUBSIDENCE BEHIND IT CLEARING SKIES OUT ACROSS THE REGION.
HOWEVER...EXTREMELY POWERFUL STORM SYSTEM IS PUNCHING INTO THE
INTERMOUNTAIN WEST AT THIS HOUR...AND WILL BE OUR MAIN WEATHER
PLAYER OVER THE NEXT 24 HOURS OR SO.

EXPECT THE DAYTIME HOURS TO BE DRY TODAY...WITH STRONG SOUTHWEST
SURFACE FLOW USHERING IN NEAR-RECORD HIGH TEMPERATURES. DON'T THINK
THAT WE'LL BE BREAKING ANY OF THE TEMP RECORDS IN PLACE (85 AT
SGF...83 AT JLN/UNO/VIH)...BUT WILL CERTAINLY BE CLOSE. WILL NEED
TO ALSO WATCH SFC WINDS DURING THE DAY TODAY AS THEY GUST INTO THE 30-40
MPH RANGE. REALLY DON'T THINK THAT WE'LL BE GETTING INTO ADVISORY
CRITERIA (30 MPH SUSTAINED...GUSTS 45+)...BUT IT'LL BE QUITE WINDY
NONETHELESS. 160 KT UPPER JET EXPECTED TO BE ROUNDING THE BASE OF
THE UPPER TROUGH BY THIS EVENING...WHICH WILL RESULT IN BEGINNINGS
OF BOMB CYCLOGENESIS OVER THE GREAT LAKES REGION. FORTUNATELY FOR
THIS NECK OF THE WOODS...WE'LL ONLY BE DEALING WITH A STRENGTHENING
OF THE SFC PRESSURE GRADIENT AND SHARPENING OF A STRONG COLD FRONT
AS IT SWEEPS ACROSS THE REGION OVERNIGHT TONIGHT. CURRENT
ANTICIPATION IS TO SEE THE FRONT BEGIN TO APPROACH THE NORTHWESTERN
CWA AROUND 00-03Z...AND BE EAST OF THE FORECAST AREA BY OR SHORTLY
AFTER 12Z. WOULD ANTICIPATE SEEING AREA OF RAIN AND EMBEDDED
THUNDER ALONG THE LEADING EDGE OF THE FRONT AS IT MOVES THROUGH THE
AREA. INSTABILITY PROGGED TO BE QUITE MINIMAL AHEAD OF THE
FRONT...BUT EXTREME DYNAMICS OF THE SYSTEM COULD MAKE UP FOR THE
LACK OF APPRECIABLE CAPE AT TIMES. IF NOTHING ELSE...VERY STRONG
WINDS JUST OFF THE DECK WON'T REQUIRE MUCH TO BE MIXED TO THE
SURFACE...AND COULD ACHIEVE 50 KT MARK WITHOUT TOO MUCH TROUBLE. STILL
THINK THAT THREAT IS RATHER LIMITED...THOUGH PER SPC DY1
OUTLOOK...CERTAINLY NOT ZERO.

FRONT PASSES THROUGH THE AREA BY 12-15Z TUESDAY...WITH RAPIDLY
CLEARING SKIES IN ITS WAKE. SFC PRESSURE GRADIENT EXPECTED TO STILL
BE PRETTY HEALTHY OVER THE NORTHERN FORECAST AREA. EXPECT TUESDAY
TO QUICKLY REMIND US THAT ITS LATE OCTOBER...WITH TEMPS SOME 10-15
DEGREES COOLER THAN ON MONDAY...ALONG WITH A BRISK WESTERLY BREEZE.

FOR THE EXTENDED...SWIFT ZONAL FLOW MIDWEEK LOOKS TO GIVE WAY TO
NORTHWEST FLOW AS UPPER RIDGING AMPLIFIES OVER THE ROCKIES AND
EVENTUALLY TRANSLATES EAST BY THE END OF THE WEEK. DEEP CANADIAN
HIGH PRESSURE PROGGED TO DROP OVER THE CWA THURSDAY NIGHT...WHICH
SHOULD RESULT IN EXCELLENT RADIATIONAL COOLING CONDITIONS. WITH
THAT IN MIND...HAVE TRENDED LOWS DOWN A COUPLE OF DEGREES FROM
MODELS THAT EVENING. OTHERWISE...SOME HINTS OF LOW END POPS TOWARD
THE WEEKEND WITH POSSIBLE TROUGH PASSAGE AND COLD FROPA...BUT
CONFIDENCE IS TOO LOW TO INCLUDE IN THE FORECAST ATTM.

BOXELL

&&

AVIATION...

DEALING WITH IFR CONDITIONS AT THE KSGF TERMINAL AT THIS TIME.
BELIEVE CONDITIONS WILL BEGIN TO IMPROVE AS CIRRUS MOVES IN FROM
THE NORTHWEST. FOG DEPTH ESTIMATED TO BE ABOUT 250 METERS THICK
FROM JUST RELEASED RAWINSONDE. EXPECT IT TO BURN OFF QUICKLY
AFTER SUNRISE.

OTHERWISE EXPECT VFR CONDITIONS FROM MID MORNING THROUGH THE
REMAINDER OF THE PERIOD. WINDS WILL BEGIN TO PICK UP BY LATE
MORNING WITH GUSTS OVER 20KTS AS THE SURFACE FRONT APPROACHES THE
AREA.

EXPECT CEILINGS TO LOWER ALSO WITH APPROACH OF THE FRONT. SHOWERS
AND A FEW THUNDERSTORMS ARE EXPECTED TO BE SCATTERED IN NATURE
WITH THE APPROACH OF THE FRONT. LOW LEVEL WIND SHEAR WILL ALSO BE
POSSIBLE FROM ABOUT 00Z UNTIL AFTER THE FRONT PASSES.

GAEDE

&&

FIRE WEATHER...

SFC TEMPS TODAY EXPECTED TO WARM INTO THE LOW 80S AT MOST
LOCATIONS...WITH SOUTH WINDS SUSTAINED BETWEEN 20 AND 25 MPH WITH
GUSTS 30 TO 35 MPH DURING THE DAY AND THIS EVENING. WHILE RH
VALUES EXPECTED TO REMAIN WELL ABOVE RED FLAG CRITERIA...WARM
TEMPS AND STRONG WINDS MAY RESULT IN FIRE CONCERNS. STRONG COLD
FRONT WILL SHIFT WINDS TO WEST THIS EVENING AND OVERNIGHT...AND
BRING WITH IT LOWER RH VALUES FOR MUCH OF THE REMAINDER OF THE
WEEK. CURRENT FORECASTS INDICATE THAT RH VALUES TUES-FRI WILL BE
IN 25-35% RANGE IN MANY PLACES...WITH WINDS 10-15 MPH.

BOXELL

&&

SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

Weather Information from www.artmorris.com