720
FXUS63 KTOP 052009
AFDTOP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
209 PM CST MON JAN 5 2026
KEY MESSAGES
- CHANCES FOR RAIN ON THURSDAY (40-80%) ARE TRENDING HIGH FOR PARTS
OF NORTHEAST AND EAST CENTRAL KANSAS. RAIN AMOUNTS COULD RANGE FROM
A QUARTER OF AN INCH WEST TO JUST SHY OF AN INCH EAST.
- THERE IS 30-40% CHANCE OF RAIN CHANGING TO SNOW FRIDAY AFTERNOON
AND FRIDAY NIGHT ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST
KANSAS.
- TEMPERATURES FRIDAY THROUGH SUNDAY ARE EXPECTED TO BE COOLER AND
CLOSER TO SEASONAL NORMALS.
DISCUSSION
ISSUED AT 209 PM CST MON JAN 5 2026
A LOW AMPLITUDE PATTERN WAS NOTED FROM THE 19Z WATER VAPOR IMAGERY.
A SUBTLE SHORTWAVE APPEARED TO BE COMING OUT OF THE CENTRAL ROCKIES
WITH AN UPPER TROUGH OFF THE WEST COAST. AT THE SURFACE, AN AREA OF
LOW PRESSURE WAS NOTED OVER CENTRAL KS. SOUTHERLY FLOW AHEAD OF THIS
FEATURE PROMOTED GOOD MOISTURE ADVECTION AND THE LOW CLOUDS THAT
PERSISTED INTO THE AFTERNOON.
A SOMEWHAT ZONAL PATTERN IS FORECAST TO PERSIST OVER THE CENTRAL
PLAINS INTO WEDNESDAY WITH THE ONLY DISTURBANCE PROGGED BY THE
MODELS TO PASS JUST NORTH OF THE FORECAST AREA THIS EVENING. DRY AIR
IN MID LEVELS AND AN INVERSION OVER THE BOUNDARY LAYER MOISTURE
MEANS THE WEAK SHORTWAVE SHOULD PASS WITHOUT GENERATING ANY SENSIBLE
WEATHER. THIS WAVE SHOULD PULL THE SURFACE LOW EAST OF THE AREA THIS
EVENING ALLOWING WEAK WESTERLY LOW LEVEL FLOW TO DEVELOP. WITH SOME
MODEST DRY AIR ADVECTION IN LOW LEVELS, LOW CLOUDS OR FOG ARE NOT
EXPECTED TO RETURN TONIGHT. WEAK COLD AIR OR NEUTRAL TEMP ADVECTION
THROUGH THE AFTERNOON TUESDAY IS EXPECTED TO KEEP AFTERNOON HIGHS
FROM WARMING TO MUCH. WITH ONLY SOME THIN CIRRUS EXPECTED THROUGH
THE DAY, HAVE BEEN A LITTLE MORE OPTIMISTIC WITH HIGHS AROUND 60
THINKING INSOLATION SHOULD HELP WARM THINGS. A MORE SOUTHERLY
COMPONENT TO THE WINDS ON WEDNESDAY ARE FORECAST TO BUMP TEMPS INTO
THE LOWER AND MIDDLE 60S.
AN AMPLIFYING UPPER TROUGH LATER THIS WEEK IS FORECAST TO KICK OUT A
LEAD SHORTWAVE ON THURSDAY. THERE IS PRETTY GOOD CONSENSUS AMONG THE
OPERATIONAL SOLUTIONS FOR THIS AND HAS RESULTED IN THE NBM TO
INCREASE POPS FOR THE EASTERN HALF OF THE FORECAST AREA INTO THE
LIKELY CATEGORY. THIS SEEMS PLAUSIBLE AND HAVE KEPT THIS WITHOUT
CHANGE. THE GOOD NEWS IS TEMPS LOOK TO REMAIN ABOVE FREEZING THROUGH
THURSDAY EVENING FOR THE PRECIP TO BE ALL RAIN.
THE MORE CHALLENGING PART OF THE FORECAST IS WHETHER A BAND OF
PRECIP DEVELOPS WITHIN THE COLD AIR FRIDAY AFTERNOON AND FRIDAY
NIGHT ACROSS CENTRAL KS. BASED ON THE 00Z ENSEMBLES, THE GFS
ENSEMBLE MEMBERS SEEMS TO BE A DRY OUTLIER TO THE ECMWF AND CANADIAN
ENSEMBLES. MY CONCLUSION IS THE 00Z ECMWF AND CANADIAN MEMBERS ARE
MORE AMPLIFIED WITH THE OVERALL PATTERN AND GENERATE A MORE ROBUST
LOW LEVEL RESPONSE SEEN AT 850MB ALLOWING MOISTURE TO LINGER INTO
THE COLD AIR WITH BETTER BAROCLINICITY PROMOTING SOME FRONTOGENESIS.
INTERESTINGLY THOUGH ONLY ABOUT 40 PERCENT OF THE ECMWF ENSEMBLE
MEMBERS FELL INTO THE CLUSTER THAT MOST RESEMBLED THE 00Z
OPERATIONAL ECMWF. SO IT IS NOT A SURPRISE TO SEE THE 12Z ECMWF BACK
OFF ON THE BANDED PRECIP INTO FRIDAY NIGHT. ALSO IT SEEMS LIKE THE
12Z GFS HAS TRENDED MORE TOWARDS THE AMPLIFIED SOLUTION. THERE
REMAINS SOME SPREAD AND LOWER PREDICTABILITY IN THE FORECAST FOR
FRIDAY AND FRIDAY NIGHT, SO HAVE STAYED WITH THE BLENDED MEAN THAT
HOLDS ONTO SOME CHANCE POPS FRIDAY NIGHT. BUT THE SETUP SEEMS TO FIT
WITH A CONCEPTUAL MODEL FOR BANDED PRECIP WITHIN THE COLD AIR. WILL
HAVE TO SEE IF LATER RUNS CONTINUE TO TREND THIS WAY. BECAUSE THE
FORECAST IS USING THE MEAN THAT HAS A LOT OF ZERO QPF SOLUTIONS, THE
FORECAST ONLY MESSAGES A CHANCE FOR LIGHT SNOW ACCUMULATION. HOWEVER
THE ENSEMBLES SUGGEST THAT IF THE BAND DOES SETUP, THE HIGH END OF
SNOW AMOUNTS FOR PARTS OF NORTH CENTRAL KS COULD BE A COUPLE INCHES
OF SNOW. SO THIS WILL BE SOMETHING TO KEEP AN EYE ON DUE TO THE
POTENTIAL IMPACTS TO TRAVEL FRIDAY NIGHT.
THE WAVE AND FORCING FOR PRECIP ARE PROGGED TO MOVE EAST OF THE
FORECAST AREA FOR SATURDAY WITH NORTHWEST FLOW REDEVELOPING FOR THE
WEEKEND AND INTO NEXT WEEK. AFTER A COOL DOWN SATURDAY, TEMPS ARE
FORECAST TO MODERATE INTO THE BEGINNING OF NEXT WEEK WITH DRY
WEATHER PERSISTING.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1037 AM CST MON JAN 5 2026
LATEST SATELLITE IMAGERY SHOWS THE STRATUS TAKING IT'S TIME MIXING
OUT. HAVE UPDATED TO KEEP SOME RESTRICTED CIGS IN THROUGH MID
AFTERNOON BASED ON THE RAP FORECAST SOUNDINGS. THINK THE NAM IS
HOLDING ON TO THE LOW LEVEL SATURATION TO LONG. A WEAK WAVE PASSES
EAST THIS EVENING CAUSING LOW LEVEL FLOW TO BECOME WESTERLY. THIS
SHOULD PROMOTE SOME DRY AIR ADVECTION AT THE SURFACE AND KEEP VFR
CONDITIONS IN PLACE THROUGH TUESDAY MORNING.
TOP WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...WOLTERS
AVIATION...WOLTERS
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