188
FXUS63 KTOP 281707
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1207 PM CDT Tue May 28 2024

.KEY MESSAGES...

- Pleasant weather continues through midweek.

- Off and on rain and storm chances enter the forecast again by
  Thursday into next week.

&&

.DISCUSSION...
Issued at 309 AM CDT Tue May 28 2024

Early this morning, an amplified upper trough was located across
Quebec, Canada extending south-southwest across Great Lakes
States into the mid MS River Valley. A second upper trough was
digging southeast out of east central Canada into northern MN.
Northwest flow aloft was noted across the Plains with a few
embedded perturbations across western NE. An amplified upper
trough was located across the Gulf of Alaska and extended
southward across the northeast Pacific, off the Pacific
Northwest coast.

The 7Z surface map showed a cold front along the central Gulf of
Mexico shoreline. The front then extended northwest as a warm front
across southeast TX, northwest into north central TX, where it
intersected a dryline west of ABI. South of the surface front
dewpoints were in the lower to mid 70s across southern and central
TX.

Today through Wednesday:

The H5 Trough across the Great Lakes and mid MS River Valley will
shift east while the h5 trough digging southeast out of
northern MN will phase with the main H5 trough across the
eastern Great Lakes and OH River Valley. The weak perturbation
combined with WAA/isentropic lift ahead of the richer moisture
advecting into western OK and southwest KS will cause showers
and perhaps a few thunderstorms to develop across west central
KS this morning. These showers and storms will move southeast
into south central KS. The northeast fringe of the shower and
thunderstorms may clip the southwest counties. The RAP and NAM
nest show a few showers developing farther east across the CWA
but the HRRR, ARW and Fv3 show the greater chances for showers
remaining southwest of the CWA through the early afternoon hours
with only a few isolated showers or storms clipping the far
southwest and southern counties. MUCAPE will only be 100-200
J/KG across the southwest counties, just enough instability for
some weak thunderstorms. Mid clouds will increase through the
mid morning hours and there may be some broken cloud cover at
times late this morning and early this afternoon. The northeast
and eastern counties will see more insolation. Highs this
afternoon will reach the lower 80s.

On Wednesday, the H5 trough over the eastern Pacific will move
onshore across the Pacific northwest. A down stream H5 ridge will
amplify across the northern and central Plains. The richer moisture
return will shift a bit farther west across the TX Pnhdl and
western KS. At the surface a ridge of high pressure will build
southward out of IA into northern MO and far northeast KS. Slightly
cooler and drier air will advect westward across the CWA. Highs will
reach the upper 70s to lower 80s Wednesday afternoon.

Wednesday night through Tuesday:

A lee sfc trough will deepen as the H5 trough moves east across
the central Rockies on Thursday. Richer moisture will advect
northward across eastern KS late Wednesday night into Tuesday
morning. Isolated to scattered elevated thunderstorms may
develop in the early morning hours of Thursday. The H5 trough
over the central Rockies will lift northeast across the northern
Plains. Both the ECMWF and GFS forecast a southern stream H5
perturbation to move east across KS and OK Thursday night into
Friday. This may be our best chance for showers and
thunderstorms ( 60 percent or greater on Friday). Severe
thunderstorm chances will be low, since the vertical wind shear
will remain weaker given the H5 westerly winds will only be 15
to 20 KTS. So, I`m not expecting widespread severe
thunderstorms. However, if the instability is higher there may
be a few strong to marginally severe storms on Friday.

Saturday, we may see a break in the rain chances as a low amplitude
southern stream H5 ridge moves east across the southern Plains.

Saturday night through Tuesday, the southern stream zonal flow will
allow embedded perturbations to move across KS and the southern
Plains. Precip chances will depend on the timing and amplification
of these perturbations. The GFS brings a front through the area on
Monday, which could bring in a slightly drier and cooler airmass
on Tuesday and end our rain chances. The ECMWF is about 24
hours slower brining the front through the regions, so if the
ECMWF verifies, rain and storm chances may extend into Tuesday.
But both the ECMWF and GFS show a PNA pattern developing with a
longer wave length trough across the eastern US and a broad
amplified ridge axis across the west central US. This will keep
the Plains in a dry northwest flow pattern from the middle of
next week through the end of the week into the following
weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1203 PM CDT Tue May 28 2024

Little changes to the going forecast with VFR conditions in
place. Could be a few passing showers at times, especially over
KMHK. The chance of this is very low and VFR conditions would
still be likely.

&&

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

&&

$$

DISCUSSION...Gargan
AVIATION...Drake