Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Grand Forks ND
631 PM CDT Tuesday Oct 21 2014

Update...
issued at 628 PM CDT Tuesday Oct 21 2014

No update necessary.

&&

Short term...(this evening through Wednesday night)
issued at 307 PM CDT Tuesday Oct 21 2014

Winds are the issue this evening. 925 mb winds increase to 50 kts
in the Red River valley 00z-06z. With the setting sun there will
be an increasing inversion but still enough pressure gradient and
winds just off the surface to keep south-southeast winds gusty all
night. This will in turn keep low temperatures warmer with some areas of
eastern ND staying above 50. Second issue is advection of low level
moisture and 850 mb instability into south central and then
eastern ND 09z-12z period. Moisture initially quite weak but precipitable waters
do go above 1 inch by 12z in the Red River. Main forcing at the surface west
of the forecast area but NAM/GFS do so MUCAPES in the 500-700 j/kg
range with NAM around 1000 j/kg at 12z Wednesday in the Red River. Also seeing
a band of 50 dew points in western Kansas into central Nebraska likely headed
for eastern ND Wednesday morning. In this 50 dew pt area there was
some low clouds. Unsure if that will occur in our area 12z Wednesday but
nonetheless conditions set up are favorable for isolated convection
late tonight in parts of eastern ND spreading into the Red River toward 12z.
Will keep mention of thunder through 18z as instability ribbon
(showwalters in the -2c range) moves into western Minnesota. Will maintain
isolated T into early afternoon for far eastern forecast area. This instability
axis is just ahead of the main push of moisture and the trough
that will be moving through. Coordinate with other offices yielded a bit
faster solution than European model (ecmwf) and most of the precipitation exits the eastern
forecast area near 06z Thursday.

Amount of rainfall not impressive with most sites under one
quarter inch...though heavier totals approaching one half inch
possible in west-central-north central Minnesota zone from Fergus Falls to Bemidji mainly
Wednesday middle to late afternoon-early evening.

Long term...(thursday through tuesday)
issued at 307 PM CDT Tuesday Oct 21 2014

Clearing will work in late Wednesday night into Thursday as winds turn
west. Any 850 mb cooling will be negated by a favorable west wind
which is good for warm surface temperatures. Thus no cooling expected for
Thursday. West wind and warmer 850 mb temperatures on Friday favor the warmer
side of most guidance values with 60s to lower 70s.

Friday night into Tuesday...overall dry weather pattern to continues
through the weekend then chance precipitation Monday/Tuesday as 500mb ridging
transitions to southwest flow aloft with approaching long wave
trough. Temperatures will go from above normal...60s Saturday and Sunday...
to near normal with strong frontal passage on Monday with highs in the upper
40s to 50 for Monday and Tuesday.

&&

Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 628 PM CDT Tuesday Oct 21 2014

Will stay mainly clear and windy most of the night. Low confidence
on coverage of potential elevated convection towards morning so
left out of tafs for now. Will be seeing an increase in middle/upper
level clouds as front approaches.

&&

Fgf watches/warnings/advisories...
ND...none.
Minnesota...none.
&&

$$

Update...voelker
short term...Riddle
long term...jk/Riddle
aviation...voelker

National Weather Service Glossary of Abbreviations