Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Grand Forks ND
931 am CDT Tuesday Sep 2 2014
issued at 928 am CDT Tuesday Sep 2 2014
Made some very minor pop adjustments through the am...keeping any
probability of precipitation north of I-94...otherwise no changes.
Update issued at 645 am CDT Tuesday Sep 2 2014
Minor tweaks made to the probability of precipitation for the morning into the afternoon.
Regional 88d/metars show -shra moving into dvl basin extending
southwest to vicinity khze. Based on current/forecast movement and hi-
res model forecast have introduced isolated -shra into central Red River.
Short term...(today through wednesday)
issued at 345 am CDT Tuesday Sep 2 2014
The next shortwave and associated -shra/thunderstorms and rain cluster moving
across northwest nodak and forecast to enter County warning forecast area just before
sunrise. Have started the morning with rain showers as currently no
lightning and there is little instability at this time. Suspect the best
risk for thunderstorms and rain across the northern half County warning forecast area per nam12 depiction
of showalters and ml cape. High temperatures today should be close
to or slightly above mondays with warm air advection and higher heights.
For tonight have kept low probability of precipitation far northeast County warning forecast area in proximity to
boundary...weak instability and 700 warm air advection. With southerly flow
gradually increasing and low level moist increase expect lows
Wednesday morning about 5 degrees warmer than this morning.
For Wednesday upper flow begins to transition from flat west-
northwest to southwest as well advertised stronger wave impacts
region. Surface low developing in western High Plains generates
increasing moist flow. A warm front is expected to lay roughly
east/west along the Dakotas border. An inverted trough develops
from the tri-state area into northeast Minnesota. Have placed
best risks along the boundary. Models disagree on amount of
instability by later Wednesday but there is a potential for a
relatively late season severe weather event over part of the
County warning forecast area.
Long term...(wednesday night through monday)
issued at 345 am CDT Tuesday Sep 2 2014
Wednesday night am currently looking for an ongoing convective
event over large parts or the region. GFS/NAM/Gem/ECMWF in fair
agreement that surface low will be over the eastern Dakotas with
moderate to strong instability and forcing...for early September
over the County warning forecast area.
For Wednesday night a modest rain event is possible depending on
the exact track of the surface low and middle level circulation.
As low moves off Thursday expect the precipitation to end fairly
early. Breezy northwest winds likely with gusts over 30 miles per hour.
Friday through Monday...the period will start off fairly quiet
with northwesterly flow aloft and high pressure over the northern
plains. Temperatures for Friday and Saturday should be slightly below
seasonal averages even with plenty of sunshine. The next upper
trough will begin to dig into the Pacific northwest on
Sunday...with a trough of low pressure starting to develop over
the northern rockies. Southerly winds Sunday and into Monday will
bring warmer temperatures to the area...and included the low probability of precipitation
that allblend gives US as warm air advection could bring some
precipitation back into the area. Think however that the better chances
for precipitation will hold off until after day 7 when the main upper
trough moves out into the plains.
Aviation...(for the 12z tafs through 12z Wednesday morning)
issued at 630 am CDT Tuesday Sep 2 2014
VFR ceiling/visibility expected today with isolated -shra this morning with isolated
-tsra after noon. Coverage does not warrant a mention at this time except
vcsh kdvl this morning. Southwest surface winds should increase with
gusts 20kts to 25kts after 18z. Higher gusts possible vcsh. Winds
should diminish quickly after 00z becoming lt 10kts after sunset.