Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 08/25/21

Area Forecast Discussion

National Weather Service Grand Forks ND

 1014 PM CDT Tue Aug 24 2021

.UPDATE...
Issued at 1006 PM CDT Tue Aug 24 2021

Cold front currently extends from around LOW into west-central MN
trekking eastward. This is increasing winds around 10-20 mph out
of the northwest along with increasing cloud cover just behind the
front. A few showers with a rumble of thunder or two may be
possible near the international border in MN before 1 AM.

UPDATE Issued at 649 PM CDT Tue Aug 24 2021

Confidence is increasing for very unlikely thunderstorms chances
late this afternoon, and attendant severe potential. Have reduced
PoPs across the area as a result.

Despite cold fropa yet to move through the area (currently
traversing the RRV) and at least weak instability ahead of the
front, confidence is increasing that chances for further
thunderstorm development is waning. Recent aircraft soundings
(AMDARs) into Fargo reveal much shallower lapse rates between
H9-H7 with a notable warm nose centered around 750 mb. This lends
confidence in a stronger cap than what is being advertised by CAM
soundings. While low level forcing from the cold fropa is present,
albeit on the weaker side, water vapor imagery is devoid of
notable signals of ascent over the area or upstream within the
western Dakotas. The only area that may see additional weak
showers resides near the int`l border closer to the upper
shortwave in Canada. The first area are some weakening convection
near LOW, and potentially additional, post frontal showers as
evidenced by shallow ACCAS currently entering the northern RRV.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 253 PM CDT Tue Aug 24 2021

Impacts in the short term are a conditional thunderstorm risk this
evening with fropa then just temps with low impact expected
Wednesday. This afternoon and evening will continue to see short
wave and fropa moving east across the forecast area. Ahead of the
activity instability remains elevated with MUCAPE around 1000J/kg.
Given the forcing and instability isolated coverage would be
expected and is evident with a small pocket of convection east of
Devils Lake currently. This activity will move east and most
likely weaken as instability and shear is lower across the
northern valley.

Precip chances exit the area before midnight and a quiet and cool
Wednesday is setting up under a passing weak sfc high pressure.
Lows will fall into the 40s and 50s tomorrow morning. Some
stratus expected to slow the diurnal heating tomorrow especially
across the north with highs in the 60s across NE ND and 70s for
the rest of the area.

.LONG TERM...(Thursday through Tuesday)
Issued at 253 PM CDT Tue Aug 24 2021

Attention turns to the next shortwave on Thursday as ensemble
guidance is suggests showers and thunderstorms arriving Thursday
morning across the western forecast area then moving eastward
throughout the day. Depending on timing and instability, isolated
strong to severe storms may be possible, but confidence remains
low for widespread organized coverage this time. Highs again in
the 60s with cloud cover across the north and 70s south.

Friday through Monday continues the active pattern of rain chances
with 500mb southwesterly flow bringing short wave energy to the
area. Timing of the waves remains quite variable given this time
range so rain chances look possible anytime through Friday into Sunday
respectively. With respect to temperatures, near to slightly
below normal temperatures will persist through the extended.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 649 PM CDT Tue Aug 24 2021

A cold front is moving through the region this afternoon and
evening, shifting and increasing winds out of the northwest as
well as bringing a period of lowered CIGS near or below MVFR.
Lowered CIGS perhaps at times to IFR may linger in KBJI during
the early morning hours Wednesday, best chance between 09-12 UTC.

Comms outage at KDVL will continue AMD NOT SKED inclusion within
the TAFs.


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
$$

UPDATE...CJ
SHORT TERM...JK
LONG TERM...JK
AVIATION...CJ