Tuesday, April 27, 2010

Area Forecast Discussion - South Central/Southwest Missouri

FXUS63 KSGF 271135
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
635 AM CDT TUE APR 27 2010

..UPDATE TO AVIATION...

DISCUSSION...

LONG WAVE CHARTS INDICATE A PATTERN CHANGE FOR THE REGION AS A
NORTHWEST FLOW ALOFT BACKS TO SOUTHWESTERLY BY THIS WEEKEND. THE
COOL AND CLOUDY WEATHER WILL THEREFORE TRANSITION TO A WARMER AND
WETTER PATTERN. THE MAIN FORECAST FOCUS THE NEXT COUPLE OF DAYS
WAS TEMPERATURES. ATTENTION THEN TURNS TO POPS LATER IN THE WEEK.

A VIGOROUS SHORT WAVE TROUGH ANALYZED OVER CENTRAL MISSOURI THIS
MORNING WILL QUICKLY SHUNT SOUTHEAST OF THE AREA TODAY. IT IS
STILL NOT OUT OF THE QUESTION WE COULD SEE A FEW SPRINKLES FROM
WHAT WILL INITIALLY BE A DECENT STRATOCUMULUS DECK. CLOUDS WILL
FINALLY DECREASE LATE THIS AFTERNOON AND THIS EVENING. AFTER
ANOTHER DAY OF RATHER BRISK NORTHWEST WINDS...LIGHT WINDS ARE
EXPECTED STARTING THIS EVENING AS SURFACE HIGH PRESSURE SLIDES
SOUTHEAST ACROSS THE ARKLATEX. OVERNIGHT LOWS WILL BE RATHER
CHILLY...WITH LOW 40S A GOOD BET AREA WIDE.

SOUTHERLY FLOW WILL COMMENCE STARTING WEDNESDAY AS LOW LEVEL
PRESSURE GRADIENTS TIGHTEN IN RESPONSE TO LEE SIDE CYCLOGENESIS
ACROSS THE CENTRAL HIGH PLAINS. THE WEDNESDAY THROUGH THURSDAY
PERIOD THEN LOOKS RATHER WINDY. MOISTURE WILL AGAIN BE SLOW TO
RETURN IN THIS REGIME...WITH THE BEST MOISTURE INITIALLY SURGING
INTO THE SOUTHERN AND CENTRAL PLAINS. ALTHOUGH GRASSES HAVE REALLY
GREENED UP...FIRE WEATHER WILL BE SOMEWHAT OF A CONCERN FOR THE
MIDWEEK PERIOD GIVEN THE WINDY CONDITIONS AND LOW RELATIVE
HUMIDITIES. MEANWHILE...TEMPERATURES WILL RESPOND NICELY AS 850 MB
TEMPERATURES WARM INTO THE MIDDLE TEENS CELSIUS. LOW 80S LOOK
REASONABLE BY THURSDAY.

MODELS ARE STARTING TO CONVERGE ON TIMING WITH AN INCOMING UPPER
LEVEL TROUGH AND SURFACE FRONT FOR THE LATE WEEK PERIOD. THINGS
THEN BECOME MORE MUDDLED THIS WEEKEND AS MODELS ARE IMPACTED BY
CONVECTIVE PROCESSES. INITIALLY...IT APPEARS THAT OUR BEST
CHANCE FOR CONVECTION WILL BE CENTERED AROUND THE FRIDAY TIME
FRAME. VERY DIFFICULT TO TELL WHAT WILL TRANSPIRE AFTER THAT TIME.
WITH A SOUTHWEST FLOW ALOFT PERSISTING THROUGH THE WEEKEND...IT IS
QUITE LIKELY THAT THE FRONT DOES NOT GET ALL THAT FAR. WITH MEDIUM
RANGE MODELS INDICATING ANOTHER SHORT WAVE TROUGH OR TWO
TRAVERSING THE FLOW...THE WEEKEND MAY VERY WELL BE UNSETTLED. WITH
THIS SAID...HAVE INCREASED POPS AND LOWERED EXPECTED HIGHS.

AS FOR THE SEVERE THREAT...THIS REGIME SHOULD YIELD PLENTY OF
LARGE SCALE SHEAR FOR ORGANIZED CONVECTION. INSTABILITY WILL BE
THE BIGGER QUESTION...AS THE AMOUNT OF QUALITY MOISTURE RETURN IS
UNCLEAR. WILL INCLUDE A LIMITED RISK OF SEVERE IN THE HAZARDOUS
WEATHER OUTLOOK FOR THE LATE THURSDAY INTO FRIDAY TIME FRAME
GIVEN THE WIND SHEAR ALONE. THE RISK LEVEL MAY NEED TO BE
INCREASED IF CONFIDENCE INCREASES IN BETTER INSTABILITY. WILL ALSO
BE ADDING A LIMITED FLOODING RISK AS THERE APPEARS TO BE A
REASONABLE CHANCE FOR MULTIPLE ROUNDS OF THUNDERSTORMS.

SCHAUMANN

&&

AVIATION...

A STRATUS DECK WITH HIGH END MVFR CEILINGS ASSOCIATED WITH AN
UPPER LEVEL LOW MOVING THROUGH THE OZARKS WILL LIFT TO VFR BY MID
MORNING. SURFACE WINDS WILL WEAKEN TO LESS THAN 8 KNOTS BY LATE
TUESDAY AFTERNOON AS THE PRESSURE GRADIENT RELAXES WITH THE UPPER
LOW DEPARTING TO THE SOUTHEAST. SKIES WILL BECOME SKC TUESDAY
NIGHT WITH LIGHT WINDS AND SURFACE RIDGE BUILDING INTO THE
OZARKS.

ANGLE

&&

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

$$


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