National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KFGF 161405
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
905 AM CDT Tue Apr 16 2024

.KEY MESSAGES...

- Windy conditions will develop early this morning and continue
  through the afternoon. Gusts up to 55 mph can be expected at
  times within portions of southeast North Dakota, west-central
  and northwest Minnesota. There is a 30 percent chance for
  gusts higher than 55 mph particularly under heavier showers
  and weak thunderstorms.

- There is a 50% chance for greater than one inch of rainfall
  through Wednesday morning. Highest chances are across the
  Devils Lake Basin, southeast North Dakota, and west central
  Minnesota.

&&

.UPDATE...
Issued at 642 AM CDT Tue Apr 16 2024

Showers/scattered thunderstorms have started to fill in along
axis of elevated WAA and nose of strong LLJ along the Hwy 2
corridor of northeast ND. There remains a region of more stable
air farther south due to a dry pocket of BL Td`s over the
southern RRV, and rain has struggled to develop into this area.
This dry layer should shift northeast as moist BL conditions
arrive from the south long the leading edge of an approaching
warm front (already seeing this trend in SD). This dry pocket
is timed out to arrive in north central MN by late morning/early
afternoon as daytime heating starts to pick up and the result
will be a brief period of RH around 25% while winds 10-20 mph
gust to 30 mph resulting in near critical fire weather for a
brief window through 20Z in our northeast. SPS was issued for
those areas.

Regarding winds: There have been sporadic reports of 40-42 mph
gusts within the advised area so far (similar gusts outside the
advisory closer to showers/weak thunderstorms farther north).
The window where models show deepest mixing is still approaching
(14Z-20Z) so these trends align with forecast.

&&

.DISCUSSION...
Issued at 403 AM CDT Tue Apr 16 2024

A strong mid/upper low is deepening on the lee side of the central
Rockies early this morning, with the surface low now over
western Nebraska. Deep southerly southerly flow is building into
the Northern Plains with a plume of deepening moist air northward,
while drier low levels are still in place over our northeast due to
low level easterly flow out of Ontario. A strong LLJ of 50+kt is
already in place and guidance shows further strengthening this
morning as the mid level low continues to shift northeast into the
Plains. This mid/upper low will be responsible for waves or
organized rain and embedded thunder through tonight/Wednesday
morning as it transitions east-northeast. The main period of
rainfall should be today with strong forcing and organization along
deformation and and inverted trough axis. There is a trend for these
features to favor the our western and southern CWA, maintaining
drier air and lighter QPF totals in the northeast.

Regarding Strong Winds: East-southeast flow expected as the strong
(50-60kt) LLJ transition over our southern CWA and this direction has
limited analogues for high wind events in our CWA as cross valley
momentum transfer can be limited. Still, there are local terrain
effects that support some downslope in west central MN, and
conservative mixed layers would support 45-55 mph gusts across our
southern CWA today, and I expanded the advisory into southeast ND
accordingly. Some guidance that tends to carry a bias (GFS/RAP)
shows a deeper mixed layer and would actually support better chances
for warning impact winds. Considering the lack of
analogues and unfavorable direction I am not confident enough to
issue a warning based on those model mixing heights. HREF does
reflect a a 20-40% prob for greater than 55 mph winds within the
advised area. One factor that could aid in momentum transfer would
be heavy rain showers/weak thunderstorms and we can`t rule out
warning impacts.

Wednesday night-Friday: As this initial mid/upper low transitions
east-northeast it eventually merges into a second (much colder)
mid/upper low (currently over British Columbia). CAA along with
weaker energy rotating around this upper low could result in
additional light rain/snow chances through this periods. While there
is a signal for snow, probabilities for more than a dusting are very
low, and warm ground temperatures and daytime temperatures will
tend to limit impacts.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 642 AM CDT Tue Apr 16 2024

VFR conditions will transition to MVFR conditions through the TAF
period. Isolated thunderstorms are expected throughout the morning
with chances diminishing in the afternoon. Intermittent rain showers
will persist through the TAF period with ceilings lowering gradually
throughout the day. There is a possibility of IFR conditions after
00z but looking on satellite to our south I`m uncertain if we will
get ceilings 1000ft and lower during this period. Winds will begin
to shift from the east to a northerly direction around 07z for most
TAF sites. KDVL will start to shift around 04z.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Wind Advisory until 7 PM CDT this evening for NDZ038-039-049-
     052-053.
MN...Wind Advisory until 7 PM CDT this evening for MNZ002-003-015-
     016-022-023-027>031-040.

&&

$$

UPDATE...DJR
DISCUSSION...DJR
AVIATION...MM/DJR