Area Forecast Discussion
Issued by NWS Topeka, KS

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000
FXUS63 KTOP 130753
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
253 AM CDT Wed Mar 13 2024

.KEY MESSAGES...

- There is a 60 to 90 percent chance for thunderstorms this
  evening across the area.

- Some of the storms this evening could produce very large
  hail, damaging winds and a tornado or two.

- The chance for showers and storms persists through the day
  Thursday with dry and cooler weather expected this weekend.

&&

.DISCUSSION...
Issued at 253 AM CDT Wed Mar 13 2024

07Z water vapor imagery showed an upper trough over the inter-
mountain west with one shortwave lifting over the central
Rockies and a jet streak on the back side of the trough. Surface
obs indicated a weak meso-high over northeast KS with a
stationary front from southwestern OK into southwestern MO.
Decent low level moisture with dewpoints in the lower to middle
50s were noted east of this boundary over central OK.

For today and tonight, models are in good agreement with a surface
low deepening over southwestern KS as shortwave energy lifts across
the central Rockies. This should help a warm front lift north into
the forecast area by this afternoon with dewpoints in the lower and
middle 50s advecting north. The model consensus is for this warm
front to be located near or just north of the KS river valley late
in the afternoon as shortwave energy kicks out from the base of the
upper trough. With only small amounts of inhibition along the
frontal boundary and MLCAPE values progged to be between 1500 and
2000 J/kg, this shortwave looks to be the trigger for convective
development and CAMs show thunderstorms firing along and north of
the front around 00Z this evening. Additionally the wind field looks
favorable for rotating updrafts and supercell storms. In fact the
RAP is forecasting large looping hodographs suggestive of favorable
stream wise vorticity and the ability for storms to intensify rather
quickly. As the low level jet increases this evening, environmental
helicity is forecast to increase to around 300 m2/s2 near the
boundary creating a favorable setup for tornados. Steep lapse rates
would also support very large hail around two inches in diameter.
The main question is whether discrete storms will reside in the
narrow corridor with the best wind fields long enough for tornado
genesis. CAMs show thunderstorms increasing in coverage as they lift
north potentially causing disruptions of the wind field on the storm
scale. And storms may tend to become more elevated the further north
of the boundary they get. Still the environmental setup is signaling
the potential for a few tornadoes this evening along and north of
the warm front.

Models don`t really show a lot of low stratus with the low level
moisture advection today. So have kept highs in the middle 70s for
most locations given 925MB temps warming to around 20C. The
exception may be across far northern KS where low level winds remain
easterly and the warmer air fails to lift that far north. Thursday
is a little tricky for POPs. Models show the boundary remaining
across eastern KS with residual moisture still in place. But the
upper pattern shows little in the way of shortwave activity as an
upper low cuts off and retrogrades southwest. Am hesitant to go with
a dry forecast thinking there could still be some upper level
deformation within the shear axis aloft. So have some POPs in the 20
to 40 percent range. More cloud cover and the warm air advection
shifting south and east of the forecast area should keep highs
generally in the 60s.

High pressure builds in by Friday and is reinforced over the weekend
with the cutoff low remaining over the southwest and shortwave
energy passing to the northeast of the forecast area. With drier air
over the are thanks to the surface ridging, the forecast is to keep
dry weather across the area with cooler temps in the 50s and lower
60s heading into next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1151 PM CDT Tue Mar 12 2024

VFR conditions should persist into the morning hours as a meso-
high pressure system drifts across the area. The next short wave
lifting out of the southern Rockies should cause a warm front to
lift north Wed afternoon. Chances for TS along the boundary are
between 40 and 70 percent. At this time, most of the CAMs keep
the convection just north of the terminals and developing
between 22Z and 02Z. So will include a VCTS in the forecast for
this potential. For now low level clouds look to remain above
3 KFT, but low CIGS may move in after 06Z Thursday.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Wolters
AVIATION...Wolters


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