Thursday, September 30, 2010

Area Forecast Discussion - South Central/Southwest Missouri

FXUS63 KSGF 301959
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
259 PM CDT THU SEP 30 2010

DISCUSSION...

HIGH PRESSURE WAS CENTERED OVER THE CENTRAL PLAINS THIS AFTERNOON
WITH NORTHERLY WINDS HOLDING TEMPERATURES IN THE MID 70S...EVEN
WITH FULL SUN.

SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)...THE HIGH WILL
CONTINUE TO DROP TO THE SOUTHEAST TONIGHT WITH WINDS DROPPING OFF
TO LIGHT AND VARIABLE. GOOD RADIATIONAL COOLING WILL LIKELY ALLOW
SOME PATCHY FOG TO DEVELOP AROUND THE LARGER LAKES LATE TONIGHT.

ANOTHER COLD FRONT WILL MOVE ACROSS THE REGION FRIDAY NIGHT AND
EARLY SATURDAY AS A SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE
UPPER MIDWEST AND OHIO VALLEY. WE MAY SEE A FEW SHOWERS DEVELOP
OVER CENTRAL MO CLOSER TO THE SHORTWAVE TROUGH BUT EXPECT MOST
AREAS TO REMAIN DRY. THEREAFTER...WE STILL EXPECT TO SEE SOME OF
THE COLDEST AIR OF THE SEASON SPREAD INTO THE REGION AS A LARGE
AREA OF HIGH PRESSURE DROPS SOUTH OUT OF CENTRAL CANADA. THE
LATEST MET MOS IS STARTING TO DROP TEMPERATURES INTO THE UPPER 30S
SATURDAY NIGHT...WITH THE MAV MOS GOING LOWER 40S. WILL LEAN MORE
TOWARD THE COLDER MET AND GO WITH UPPER 30S ROUGHLY FROM ROLLA TO
SPRINGFIELD AND INCLUDE PATCHY FROST IN OUR WEATHER GRIDS.

TERRY

LONG TERM (SUNDAY THROUGH THURSDAY)...LONG WAVE CHARTS CONTINUE
TO INDICATE A BLOCKING RIDGE CENTERED AROUND 45 WEST. THIS WILL
LIKELY RESULT IN NEGATIVE HEIGHT ANOMALIES PERSISTING ACROSS
EASTERN NORTH AMERICA. MEANWHILE...ALL MEDIUM RANGE MODELS DIG A
STRONG SYNOPTIC SCALE TROUGH THROUGH THE GREAT LAKES AND INTO THE
OHIO VALLEY BY LATE THIS WEEKEND. THE GFS HAD BEEN ADVERTISING
THIS ENERGY SHEARING OUT AND PULLING NORTHEAST AS IT ENCOUNTERED
THE ATLANTIC RIDGE. HOWEVER...THE 12Z GFS HAS NOW COME MORE IN
LINE WITH THE LAST SEVERAL RUNS OF THE ECMWF. BOTH MODELS KEEP A
CLOSED LOW SOMEWHERE OVER THE EASTERN UNITED STATES INTO THE
MIDDLE OF NEXT WEEK. THIS MAKES MORE SENSE GIVEN THE BLOCK...AND
WHAT WILL BE A GOOD DIGGING REGIME ACROSS EASTERN NORTH AMERICA.

WITH THAT SAID...A NORTH TO NORTHWEST FLOW ALOFT WILL PERSIST ACROSS
THE REGION INTO MIDWEEK. TEMPERATURES WILL REMAIN BELOW NORMAL WITH
A SURFACE RIDGE AXIS EXTENDING FROM THE GREAT LAKES INTO THE OZARKS
REGION. MOS GUIDANCE SEEMS A TAD WARM GIVEN THIS REGIME...WITH RAW
MODEL TEMPERATURES USUALLY A BETTER PERFORMER FOR WHAT WILL BE WELL
BELOW NORMAL TEMPERATURES. LOWS IN THE UPPER 30S LOOK QUITE
REASONABLE BOTH SUNDAY AND MONDAY MORNING...WITH MIDDLE 30S VERY
POSSIBLE IN VALLEYS. PATCHY FROST WAS INSERTED INTO PORTIONS OF
CENTRAL AND SOUTHWEST MISSOURI...AS WELL AS PORTIONS OF SOUTHWEST
MISSOURI. WILL THEN NEED TO SEE HOW QUICKLY THAT SURFACE RIDGE AXIS
SHIFTS EAST TO GAUGE ANY REAL WARMUP. THE ENTIRE PERIOD LOOKS
DRY...ALTHOUGH THERE IS AN OUTSIDE SHOT FOR A SPRINKLE ACROSS
CENTRAL MISSOURI ON SATURDAY AS THAT UPPER LEVEL TROUGH DIGS
SOUTHEAST.

SCHAUMANN

&&

AVIATION...

VFR CONDITIONS WILL CONTINUE AT AREA TERMINALS THROUGH FRIDAY
MORNING AS A SURFACE HIGH PRESSURE BUILDS IN TONIGHT. PRESSURE
GRADIENT THIS AFTERNOON WILL CAUSE GUSTY NORTHERLY WINDS BUT WILL
RELAX NEAR SUNSET. CLEAR SKIES AND LIGHT WINDS TONIGHT AND FRIDAY
MORNING EXPECTED.

GRIFFIN

&&

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

$$

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