352
FXUS63 KTOP 300752
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
252 AM CDT Mon Sep 30 2024

.KEY MESSAGES...

- Temperatures remain 5-10 degrees above normal, outside of a
  brief cool down on Tuesday and next Monday.

- Dry conditions continue through the 7 day forecast.

&&

.DISCUSSION...
Issued at 226 AM CDT Mon Sep 30 2024

Early this morning a closed cut off upper low, a portion of the
remnants of Helene, continued to slowly drift east across
KY/TN. The main polar H5 jet was located across the Pacific
northwest and extened northeast towards the southern Hudson Bay
region of Canada. A more amplified upper level trough was
embedded within the northern stream H5 Jet across the Pacific
Northwest. A low amplified H5 trough embedded within the
southern stream H5 jet was moving onshore across central and
southern CA, with a downstream southern stream H5 ridge across
the Southwestern US, extending northeast into the central
Plains.

The 1 AM surface observations showed a surface ridge axis extending
from the northern Great Lakes, southwest across eastern KS. A
surface low was located across western ND, with a lee surface
trough axis extending south-southwest across the high Plains.

Today:

Expect one more hot day. However RHs will remain low with a dry air-
mass in place. The PBL will mix to around 850mb this afternoon, thus
high temperatures should reach the mid to upper 80s across the eastern
half of the CWA and around 90 degrees across the western
counties. Given the dry air-mass and deeper mixing, I went with
the 75th percentile of the NBM for this afternoon`s high
temperature forecast.

Tonight through Tuesday night:

The Pacific Northwest H5 trough will
move east across the northern Plains Tonight. The stronger low-level
CAA across the northern Plains will cause a cold front to
rapidly move southeastward across the CWA during the late
evening hours into the early morning hours of Tuesday. The
surface front will come through the CWA dry, given the lack of
surface moisture return ahead of the front and the stronger DCVA
well north of the region. Winds behind the front will switch to
the north and increase to 15 to 25 MPH with gusts to 35 MPH.
The winds will begin to diminish during the mid and late morning
hours of Tuesday.

The low-level CAA will help to keep high temperatures on Tuesday
in the lower to mid 70s, with some upper 60s across northeast
KS. A surface ridge of high pressure will move southeast across
the CWA Tuesday night. Clear skies and light winds will allow
low temperatures to drop into the mid 40s, some areas could see
lower 40s.

Wednesday through Monday:

The main H5 jet will remain across the northern US. Expect high
temperatures to warm back into the 80s Wednesday and Thursday.
A low amplitude H5 trough will move across the northern Plains
on Thursday and this may cause a weak front to push southeast
across the CWA Thursday night, cooling highs a bit on Friday
into the mid 70s to around 80 degrees. Highs will warm back up
next weekend into the lower to mid 80s. A more amplified upper
trough will move east across the northern Plains into the upper
Midwest on Sunday, this will cause a stronger surface front to
move southward across the CWA late Sunday night. Once again the
lack of richer moisture return and the QG forcing being well to
north northeast will cause the front to come through dry. The
low- level CAA on Monday will cool highs back into the 70s.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1232 AM CDT Mon Sep 30 2024

Expect VFR conditions for the next 24 hours. Patchy shallow
ground fog may develop at KTOP and KMHK just before sunrise but
should mix out by 14Z.

&&

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

&&

$$

DISCUSSION...Gargan
AVIATION...Gargan