Monday, April 26, 2010

Area Forecast Discussion - South Central/Southwest Missouri

FXUS63 KSGF 261105
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
605 AM CDT MON APR 26 2010

..UPDATE TO AVIATION...

DISCUSSION...

CURRENT CONDITIONS WITH OVERCAST SKIES AND DRIZZLE/LIGHT RAIN
CONTINUES THIS MORNING UNDER UPPER LEVEL NORTHWEST FLOW. SHOULD
SEE A PERIOD THIS MORNING BRIEFLY WHERE CONDITIONS IMPROVE
SLIGHTLY AS A TRANSIENT UPPER LEVEL RIDGE SLIDES THROUGH THE
NORTHWEST FLOW PATTERN. THIS IS IN ADVANCE OF A LOW SLIDING SOUTH
OUT OF THE NORTHERN PLAINS. THIS WILL PROVIDE THE CHANCE OF SOME
ADDITIONAL SHOWERS ACROSS THE OZARKS...ESPECIALLY FOR AREAS ACROSS
CENTRAL MISSOURI THROUGH TUESDAY MORNING. THERE IS LITTLE IN THE
WAY OF INSTABILITY FOR THIS SYSTEM THOUGH A RUMBLE OF THUNDER OR
TWO CANT BE RULED OUT THIS AFTERNOON.

THE UPPER LEVEL PATTERN WILL SHIFT OUT OF NORTHWEST FLOW WEDNESDAY
AS AN UPPER LEVEL RIDGE SLIDES OVER THE REGION. THIS WILL ALLOW
TEMPERATURES TO CLIMB TO AROUND 80 DEGREES FOR HIGHS. THIS WILL
OCCUR AS STRONG WARM AIR ADVECTION DEVELOPS AS THE SURFACE PRESSURE
GRADIENT TIGHTENS AND WINDS BECOME STRONG AND GUSTY OUT OF THE
SOUTH TO SOUTHWEST. GULF MOISTURE LOOKS LIKE IT WILL LAG A BIT AS
SURFACE HIGH PRESSURE OVER THE GULF STATES CAUSES LOW LEVEL
MOISTURE TO TAKE THE LONG ROUTE TO THE OZARKS VIA WEST TEXAS.

THIS IS THE POINT WHERE THE ECMWF/GFS/GEM BEGIN TO DIVERGE
CONCERNING THE STORM SYSTEM FOR THE END OF THE WEEK. THE GFS IS BY
FAR THE FASTEST AND MOST AGGRESSIVE IN PUSHING A COLD FRONT ALL THE
WAY THROUGH THE REGION BY FRIDAY MORNING. THE ECMWF ACTUALLY NEVER
GETS THE FRONT THROUGH THE AREA...HANGING IT UP NORTH AND WEST OF
THE OZARK PLATEAU...WHILE THE GEM IS ABOUT THE MIDDLE OF THE TWO
WITH A SLOWER FRONTAL PASSAGE WITH THE FRONT MOVING ACROSS THE
OZARKS LATE IN THE DAY FRIDAY. THE RUN TO RUN DIFFERENCES AND THE
LACK OF A CONSISTENT SIGNAL FROM THE MODELS LENDS LITTLE
CONFIDENCE IN THE TIMING AND PLACEMENT OF THE STORM SYSTEM FOR THE
END OF THE WEEK. HOWEVER...WITH BOTH THE GFS AND GEM INDICATING A
FRONTAL PASSAGE AND THE PROGRESSIVE NATURE OF THE UPPER LEVEL
PATTERN EXPECTED...THINK THAT THE ECMWF HANGING THE FRONT UP IS
THE NOT THE BEST SOLUTION. DID GO AHEAD AND USE A BLEND OF THE
THREE MODELS FOR TIMING AND PRECIPITATION CHANCES BUT WILL
DEFINITELY NEED TO MONITOR LATER RUNS FOR BETTER CONSISTENCY AND TO
HELP FOCUS IN ON THE CORRECT TIMING OF THE SYSTEM. NOT
WITHSTANDING THE TIMING DIFFERENCES...THE POTENTIAL FOR STRONG TO
SEVERE STORMS WITH THIS SYSTEM WILL REST ON THE AMOUNT OF MOISTURE
RETURN THE REGION WILL REALIZE FROM THE GULF AND THE TRACK OF THE
UPPER LEVEL LOW ACROSS THE NORTHERN PLAIN STATES.

HATCH

&&

AVIATION...

A DECK OF STRATOCUMULUS WILL CONTINUE TO RESIDE OVER THE REGION
INTO THIS EVENING. MVFR CEILINGS ARE EXPECTED TO PREVAIL AT KSGF
TODAY. KBBG AND KJLN WILL BE ON THE EDGE OF THE LOWER CLOUD DECK.
CURRENT THINKING IS THAT KBBG WILL TRANSITION FROM MVFR TO VFR
LATER THIS MORNING. KEPT KJLN VFR FOR THE ENTIRE TAF PERIOD. WINDS
WILL REMAIN BRISK AND GUSTY OUT OF THE WEST AND NORTHWEST TODAY.
CEILINGS SHOULD THEN COME UP THIS EVENING...ALTHOUGH MID LEVEL
CLOUDS WILL PERSIST. WINDS WILL DIMINISH AFTER DARK.

SCHAUMANN

&&

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

$$

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