FXUS63 KOAX 052015
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
311 PM CDT FRI NOV 5 2010
.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT.
HIGH PRESSURE AT BOTH THE SURFACE AND ALOFT WILL REMAIN THE DOMINATE
FEATURE THIS FORECAST. AIR REMAINS VERY DRY WITH WARMER TEMPERATURES
RETURNING TO THE REGION FRIDAY AND SATURDAY AS FLOW BECOMES
SOUTHERLY ON BACKSIDE OF THE HIGH. LITTLE CHANGE TO CURRENT
FORECAST WITH TEMPERATURES APPROACHING 70 IN PARTS OF THE AREA ON
SATURDAY.
FOBERT
.LONG TERM...SUNDAY THROUGH FRIDAY.
LARGE SCALE PATTERN CHANGE APPEARS TO BE SETTING UP OVER NORTH
AMERICA NEXT WEEK. THE MEAN UPPER RIDGE OVER THE WESTERN/CENTRAL
UNITED STATES DEAMPLIFIES...AND THE TROF OVER THE EASTERN UNITED
STATES SHIFTS EAST TO ALLOW FOR AN EXPANDING AND DEEPENING LONGWAVE
UPPER TROF TO MOVE THROUGH THE WESTERN UNITED STATES EARLY IN THE
WEEK AND CENTRAL UNITED STATES BY THE END OF THE WEEK. THE NOTION
OF A STRENGTHENING UPPER RIDGE IN THE EAST BY THE END OF THE WEEK
WAS FIRST SUGGESTED IN THE 240 HOUR REMOP FROM THE 00Z NOVEMBER 2ND
RUN...AND THAT INDICATION HAS CONTINUED WITH GOOD AGREEMENT WITH
EACH CONSECUTIVE RUN. THE LATEST REMOP SHOWS A HIGH PROBABILITY OF
ANCHORING RIDGES OVER THE EAST COAST OF NORTH AMERICA AS WELL AS
JUST OFF THE COAST OF WESTERN NORTH AMERICA AND INTO THE YUKON. IN
BETWEEN THERE IS QUITE LOW AGREEMENT WITH THE DETAILS OF WHAT IS
GOING ON WITH THE SHORTWAVES MOVING WITHIN THE LONGWAVE TROF OVER
THE CENTRAL UNITED STATES.
MOST MODELS BRING A SIGNIFICANT LOW PRESSURE THROUGH NEBRASKA/IOWA
MAINLY THURSDAY INTO THE FRIDAY PERIOD. IN GENERAL...THE GFS IS
FASTER AND THE ECMWF IS SLOWER. PER THE EXTENDED FORECAST
DISCUSSION FROM HPC... THERE IS REASON TO BELIEVE THE AMPLIFIED
DOWNSTREAM UPPER RIDGE SHOULD FAVOR THE SLOWER ECMWF SOLUTION WITH
THE UPPER LOW. EVEN IF THE UPPER LOW IS SLOWER TO MOVE
EAST...STRONG WARM AIR ADVECTION AHEAD OF THE LOW SHOULD BRING A
RETURN OF MOISTURE AND CHANCES FOR PRECIPITATION THURSDAY INTO
THURSDAY NIGHT.
TIME PERIOD THAT HAS THE MOST UNCERTAINTY IS THURSDAY NIGHT. THERE
IS REASONABLE AGREEMENT THAT A VERY STRONG 850MB BAROCLINIC ZONE
WILL BE OVER OR NEAR THE FORECAST AREA DURING THE LATE
THURSDAY/EARLY FRIDAY PERIOD...BUT THERE ARE WIDELY VARYING
SOLUTIONS ON THE DETAILS OF EXACTLY WHEN AND WHERE. THIS OF COURSE
HAS A GREAT IMPACT ON THE RESULTING SENSIBLE WEATHER. THE GFS
ENSEMBLE MEAN IS FAIRLY CLOSE TO THE COOL OPERATIONAL GFS...AND THE
GFS ENSEMBLE PROBABILITY OF 850 TEMP LESS THAN 0C RANGES FROM 45
PERCENT ALONG THE KANSAS BORDER TO 85 PERCENT ALONG THE SOUTH DAKOTA
BORDER DUE TO SOME FAIRLY COLD MEMBERS OF THE GFS ENSEMBLE. THE
ECMWF IS WARMER AS WOULD BE EXPECTED GIVEN THE SLOWER TROF
MOTION...HOWEVER IT DID TREND TOWARDS A COOLER SOLUTION WITH THE 12Z
RUN. EVEN WITH THE WARMER ECMWF SOLUTION...ITS 850 TEMPERATURES ARE
IN THE +1C TO +3C RANGE THURSDAY NIGHT. WITH SUCH VARYING
TEMPERATURE PROFILES IN THE EXTENDED MODELS...WE DID INCLUDE A
CHANCE FOR A RAIN-SNOW MIX OVER THE NORTHERN HALF OF THE FORECAST
AREA THURSDAY NIGHT...WITH ALL RAIN IN THE SOUTHERN HALF.
NIETFELD
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS CONTINUE THRU TAF PD AS HIGH PRESSURE MOVES OFF TO
THE SOUTHEAST. INCREASING SOUTH WINDS AS SURFACE GRADIENT TIGHTENS
OVER THE REGION.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$