991
FXUS63 KFGF 240458
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1158 PM CDT Tue Apr 23 2024

.KEY MESSAGES...

-Rain this weekend but only a 30-50% for more than an inch.

&&

UPDATE
Issued at 1054 PM CDT Tue Apr 23 2024

Winds continue their downward trend as expected with
temperatures already falling into the 34-37 range over parts of
the northern RRV. Forecast lows in mid 20s near Lake of the
Woods to the lower 30s in our south still seem reasonable. Due
to ideal radiational conditions and Tds in the teens to lower
20s across the north, it is certainly possible for colder spots
to fall below 25.

UPDATE
Issued at 659 PM CDT Tue Apr 23 2024

Winds have started to show decreasing trends northwest to
southeast. There had been sporadic obs near critical fire
weather conditions (20-25% RH and gusts around 25 mph) in
northeast ND, but these have been sporadic and localized and
with stronger gusts already decreasing there hasn`t been a
reason to introduce any enhanced fire weather messaging. Minor
adjustments were made to near term trends (mainly sky cover
clearing and winds decreasing), otherwise the forecast is on
track for tonight.

&&

.DISCUSSION...
Issued at 249 PM CDT Tue Apr 23 2024

Building low level thermal ridging continues to shift east tonight
with a surface trough moving across the valley overnight. This shift
winds from the north to the south by mid morning Wednesday. With the
exit of the upper low as this ridging moves in we lose our pressure
gradient and cold air advection from 925mb to 700mb reducing the
winds with gusts dropping off before sunset tonight. Not looking at
any notable precip chances prior to Friday as low level dry air
lingers resulting in sunny skies asides from some afternoon cumulus
tomorrow though the high dewpoint spreads at the top of the boundary
may inhibit even this. RH as low as 20-25 percent are a 30% chance
but hinge on afternoon mixing getting our temps closer to 70 than
than currently expected mid 60s for highs. This would be tied to the
strength of 700mb warm air advection though not anticipating
extremely strong WAA under the ridge axis. Thus RH closer to 30% and
no near critical fire weather as winds remain less than 15 knots.

Moving later in the week a deformation axis moves in aloft Thursday
afternoon into Friday increasing precip chances though northeast low
level flow is likely to be dry and at least initially result in
depressed precip chances. This makes sense based on pattern
recognition looking at the past 2 systems which had similar
evolutions as rain held off longer than originally anticipated. As
the main wave tracks north out of the central plains better moisture
begins to wrap in from the south with more widespread rain likely by
Friday morning depending on the arrival time of the upper low. The
inverted trough being depicted by ensemble solutions at this time
remains west of our area thus the precip should remain evenly
distributed aside from any convective pockets. Best chance for any
isolated thunderstorms will be Thursday night Friday as the max
theta-e tongue arches into the ND-SD border. Probs for greater than
100 J/kg of cape max out near 30 percent in the south but remain
tied closely to the northeast side of the low so will have to
monitor trends for any severe threat but likely at least an isolated
thunderstorm threat. Looking at greater than an 80% chance for most
areas of seeing 0.25" though pre-wave dry air could trim these
chances to favor the south and east more. For a widespread 1" or
more only seeing a 30-50% chance and would likely have to rely more
on seeing a convective shower than sustained rain to hit this
threshold.

Once this system exits the area on Saturday with high pressure
moving in behind from the north/northwest we get a short break
before another upper low looks to swing into the northern plains
Sunday/Monday. Looking to continue the active pattern into next week
with a perturbed jet stream favoring active weather across the
central US into early May. For northwest Minnesota and eastern North
Dakota look for near to above average moisture over the next 2 weeks
and similarly above average temperatures.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1158 PM CDT Tue Apr 23 2024

VFR conditions should prevail across eastern ND and northwest
MN, though there is a chance (less than 20%) for low stratus
and light ground fog to develop in the vicinity of KBJI before
sunrise Wednesday morning. Surface ridging shifting east is
already resulting in lighter winds with light and variable/calm
winds through Wednesday morning sunrise. Winds eventually
increase to the 7-11kt range from the south-southwest as
surface low pressure builds to the west and a layer of 6-10 KFT
AGL CU may develop during the midday/afternoon period (mainly in
ND). Winds eventually shift to the southeast Wednesday evening
to the 7-14kt range in eastern ND (highest near KDVL) as
surface gradient increase.

&&

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

&&

$$

UPDATE...DJR
DISCUSSION...TT
AVIATION...DJR