Area Forecast Discussion
Issued by NWS Topeka, KS
FXUS63 KTOP 241136
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
536 AM CST Sat Jan 24 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 303 AM CST SAT JAN 24 2015
Clear skies across northeast Kansas this morning as the area was
in the middle of two separate systems. The main upper trough
impacting the eastern CONUS is progressing eastward, while
northwest flow aloft across the plains is beginning to bring the
next shortwave trough southward into ND later this AM.
After lows in the upper 20s this morning, temperatures will quickly
rebound as increasing west to northwest downslope winds carry warm
h85 temps near 6C towards the CWA. Sided closer to the MOS guidance
which has trended a bit warmer than model blends with readings in
the upper 50s to low 60s for highs. Fire weather concerns reside over
north central portions of the CWA as minimum humidity values fall to
the upper 20 percentile in the late afternoon. Combined with sfc
westerly winds at 10 to 15 mph sustained may lead to high or very
high fire danger from noon through 5 pm.
For this evening, the aforementioned upper trough is progged to drop
south and east, with the axis pivoting eastern Nebraska into Iowa by
06Z. An upper jet streak rounding the upper ridge strengthens the low
as it crosses over portions of far northeast and east central areas.
With the exception of the NAM, all short term guidance indicates
light rain showers or sprinkles developing late this evening.
Chances are only slight however as moisture availability is shallow
around 4 KFT and short lived as the system quickly exits southeast.
Confidence is much higher in the stronger winds as direction shifts
to the northwest between 15 and 20 mph, gusting to near 25 mph
through the morning period.
.LONG TERM...(Sunday through Friday)
Issued at 303 AM CST SAT JAN 24 2015
By Sunday morning, models suggest the stronger forcing will have
pushed south and east of the forecast area and as a result show
little or no vertical motion. Even the ECMWF shows the PV anomaly
and stronger PVA southeast of the forecast area, so I`m not sure
why it is generating some very light QPF. In any case do not
expect measurable precip and have left POPs at 10 percent across
the eastern portion of the forecast area. Temps Sunday are looking
cooler than previously forecast. Think this in part due to
increasing clouds limiting insolation and modest cold air
advection. With this in mind, have trended Highs for Sunday down
into the mid and upper 40s.
The weather is expected to be uneventful for Sunday night through
Friday. Models continue to show energy that is left over the Baja
of California being picked up by the mean flow and coming across
the plains Wednesday night. However they persist in tracking the
stronger forcing north of the forecast area while deep moisture
remains limited. Because of this, have kept a dry forecast. There
is some disagreement between the GFS and ECMWF by Friday night in
shortwave energy diving south along the Rockies. This leads to a
possible winter storm developing in one solution while the lack of
shortwave energy keeps the region dry. At this point, any
potential storm system looks to impact the region after Friday
night. So this will be something to watch in coming model runs.
Temps should remain above normal for Monday through Wednesday as
Ridging aloft over the west gradually shifts over the plains. An
initial cold front and northerly winds for Thursday and Friday
should cool temps closer to seasonal norms. A stronger surge of
Canadian air is progged to sweep through the plains Saturday
.AVIATION...(For the 12Z TAFs through 12Z Sunday Morning)
Issued at 529 AM CST SAT JAN 24 2015
VFR prevails at KTOP/KFOE/KMHK with the wind speed/direction changes
being the main concern. Approaching wave from the north will
increase westerly winds above 10 kts as they back towards the
southwest during late afternoon. As cloud cover and disturbance
passes overhead, light sprinkles are possible however not likely
enough to mention. Some uncertainty on timing for wind shift to
northwest overnight as front approaches. Regardless northwest
winds gradually increase from 06Z to 12Z with gusts around 25 kts.
Issued at 403 AM CST SAT JAN 24 2015
THERE REMAINS SOME CONCERN WITH FIRE WEATHER AS THE FORECAST
KEEPS ABOVE NORMAL TEMPS WITH DRY WEATHER IN PLACE. WITH FUELS
BEING REPORTED AS CRITICAL, IT WOULD NOT TAKE MUCH FOR VERY HIGH
OR EXTREME FIRE DANGER TO OCCUR AND FOR PROBLEMS TO SPRING UP
TODAY THE DRY WEATHER PATTERN PERSISTS WITH GENERALLY A WEST WIND
OVER CENTRAL AND EASTERN KS. A WEAK TROUGH OF LOW PRESSURE MAY
MOVE INTO THE AREA CAUSING WINDS TO BECOME A LITTLE MORE
SOUTHWESTERLY. FORTUNATELY WIND SPEEDS ARE EXPECTED TO BE IN THE
10 TO 15 MPH RANGE. ADDITIONALLY MIN RH VALUES ARE FORECAST TO
RANGE BETWEEN 25 AND 30 PERCENT. SO THINK RANGELAND FIRE DANGER
WILL BE HIGH THIS AFTERNOON. IF WINDS ARE A LITTLE STRONGER OR
HUMIDITY A LITTLE LOWER, WE MAY SEE SOME VERY HIGH FIRE DANGER
ACROSS NORTH CENTRAL KS. MIXING HEIGHTS ARE NOT EXPECTED TO BE
VERY DEEP THIS AFTERNOON, BUT TRANSPORT WINDS AROUND 20 MPH SHOULD
BE SUFFICIENT FOR GOOD TO EXCELLENT SMOKE DISPERSAL CONDITIONS.
A STORM SYSTEM IS PROJECTED TO PASS TO THE NORTHEAST OF THE AREA
ON SUNDAY. THIS IS LIKELY TO CAUSE STRONGER NORTHWEST WINDS
GUSTING OVER 30 MPH. BECAUSE OF THIS THERE IS THE POTENTIAL FOR
ELEVATED CONCERN. THE SYSTEM THOUGH SHOULD ALSO BRING COOLER TEMPS
AND IN TURN HIGHER HUMIDITY LEVELS. AT THIS POINT, MIN RH VALUES
ARE FORECAST TO BE AROUND 40 PERCENT.