684
FXUS63 KGID 210909
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
309 AM CST SAT NOV 21 2009
DISCUSSION...ALOFT
SHORTWAVE RIDGING WAS IN PLACE ACROSS THE
CENTRAL PLAINS WHILE TO THE WEST...A TROUGH STRETCHED FROM BRITISH
COLUMBIA SOUTH THROUGH THE ROCKIES. THE SHORTWAVE RIDGE AXIS WILL
SHIFT EASTWARD TODAY AS THE WESTERN TROUGH ADVANCES TO THE EAST. AT
THE SURFACE THE ASSOCIATED TROUGH WILL DEEPEN IN THE LEE OF THE
ROCKIES AND THE GRADIENT WILL TIGHTEN...RESULTING IN INCREASING
SOUTHERLY WINDS TO THE BREEZY CATEGORY AT TIMES. CLOUD COVER FOR
TODAY IS CHALLENGING AS AN AREA OF STRATUS CURRENTLY LOCATED
ACROSS CENTRAL/SOUTHEAST KANSAS WILL WORK ITS WAY NORTHWARD DURING
THE DAY. OUR SOUTHERN CWA MAY SEE SOME FOG DEVELOPMENT THIS
MORNING AND WILL CONTINUE TO MONITOR TRENDS OF THIS IN THE NEXT
FEW HOURS. WHETHER OR NOT THE LOW CLOUDS MIX OUT TODAY REMAINS IN
QUESTION AS THE NAM SUGGESTS THIS IS MORE PROBABLE THAN THE GFS
WHICH MAINTAINS CLOUD COVER ACROSS THE MAJORITY OF OUR CWA FOR
MUCH OF THE DAY. CONFIDENCE IS NOT HIGH IN THIS REGARD AND DID OPT
FOR A CONSERVATIVE APPROACH WITH SOME CLOUDS AROUND.
TONIGHT...THE TROUGH AXIS BEGINS TO PUSH EAST OF THE ROCKIES AND
SOUTHWESTERLY FLOW ALOFT IS ENHANCED ACROSS THE PLAINS. MOISTURE
CONTINUES TO ADVECT NORTH AHEAD OF THE SURFACE BOUNDARY WHICH
APPROACHES OUR WESTERN CWA SUNDAY MORNING. STRATUS IS EXPECTED TO
SETTLE IN ACROSS OUR CWA AHEAD OF THE SURFACE BOUNDARY. WINDS WILL
BE LIGHT ALONG THE BOUNDARY AXIS AND THE NAM IS THE MOST
AGGRESSIVE IN SUGGESTING THE POTENTIAL FOR THE DEVELOPMENT OF
DENSE FOG VS THE GFS. SREF PROBABILITIES LEND CREDENCE TO THE NAM
AND HAVE INCLUDED SOME LOW VISIBILITY POTENTIAL IN THE GRIDS BUT
STOPPED SHORT OF ADVISORY CRITERIA FOR NOW. WEAK LIFT OVER THE
SHALLOW LOW LEVEL MOISTURE MAY LEAD TO THE DEVELOPMENT OF SOME
DRIZZLE.
THE TROUGH/WAVE MOVES THROUGH ON SUNDAY AND THIS SYSTEM MAY GENERATE
SOME LIGHT PCPN IN THE AFTN IN OUR EAST WHERE BETTER MOISTURE IS
PRESENT. THE WAVE DOES NOT EFFECTIVELY SCOUR THE LOW LEVEL MOISTURE
AND HAVE SOME CONCERNS THAT THE STRATUS WILL REMAIN SUNDAY NIGHT AND
FOG MAY DEVELOP AGAIN. HAVE INTRODUCED SOME PATCHY FOG FOR NOW AS
A START.
THE FORECAST TURNS MORE INTERESTING ON MONDAY AS ANOTHER TROUGH DIGS
SOUTH FROM THE NORTHERN ROCKIES AND IS FORECAST TO CLOSE OFF ACROSS
THE PLAINS ON MONDAY. MODELS HAVE VARIED ON WHERE THE LOW WILL
CLOSE OFF/TRACK WITH THE GFS REMAINING FARTHER NORTH THAN THE
NAM/ECMWF/GEM. HAVE TRENDED TOWARD THE SOUTHERN SOLUTION FOR NOW
WITH PCPN CHCS INCREASING ON MONDAY AHEAD OF THE SYSTEM AND
CONTINUING MONDAY NIGHT/TUESDAY IN THE DEFORMATION/WRAPAROUND. THE
PREDOMINATE PCPN TYPE SHOULD BE RAIN INITIALLY BUT A R/S MIX OR A
CHANGEOVER TO SNOW W/E ON THE BACK SIDE OF THE SYSTEM IS POSSIBLE
MONDAY NIGHT INTO TUESDAY. IN ADDITION THE PCPN POTENTIAL...VERY
STRONG WINDS ON THE BACK SIDE OF THE SYSTEM WILL BUFFET OUR REGION
MONDAY NIGHT/TUESDAY WITH WIND GUSTS OVER 40 MPH POSSIBLE.
AVIATION
06Z TAF. MAIN CONCERN FOR THE TAF PERIOD IS THE
POTENTIAL FOR THE ARRIVAL OF STRATUS JUST AFTER DAYBREAK ON
SATURDAY. THE LEADING EDGE OF THE STRATUS CLOUDS IS LOCATED ACROSS
SOUTH CENTRAL KANSAS ATTM AND WITH INCREASING SOUTHERLY FLOW
OVERNIGHT AND SATURDAY...THE LOW CLOUDS WILL ADVECT NORTHWARD. FOR
NOW HAVE KEPT CEILINGS IN THE MVFR RANGE FOR A FEW HOURS AND THEN
SCATTERED THE CLOUDS IN THE AFTERNOON. IN A TIGHTENING SURFACE
GRADIENT...SOUTHERLY WINDS WILL INCREASE ON SATURDAY WITH GUSTS
AROUND 25KTS POSSIBLE.
GID WATCHES/WARNINGS/ADVISORIES
NE...NONE.
KS...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page