Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/04/20
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
928 PM CST Tue Nov 3 2020
Issued at 927 PM CST Tue Nov 3 2020
Not planning any major updates tonight. Forecast is in good shape.
.SHORT TERM...(This Evening through Wednesday Night)
Issued at 147 PM CST Tue Nov 3 2020
The forecast challenge is temperature.
Currently, westerly breezes are helping the already warmer than
normal airmass over-achieve, temperature-wise, again today. A,
literally, cloudless sky over this CWA and these warm west winds are
pushing the mercury up into the upper 60s to upper 70s throughout
the forecast area. Continuing with the Red Flag Warning that covers
Corson, Dewey, Campbell, Walworth, Potter and portions of McPherson,
Edmunds and Faulk counties through 5 PM CST. Have already met red
flag criteria across a few spots in fire weather zone 268, and
suspect that those conditions will be met even further east across
portions of fire weather zone 269 before sundown.
At risk of sounding like a broken vinyl record, the much above
normal and precipitation-free forecast will persist into Wednesday.
Similar to this morning, looking at low temperatures tonight and
Wednesday night dipping into the 30s and 40s. High temperatures on
Wednesday will likely warm well into the 60s and 70s, per 12Z
deterministic 925hpa/850hpa thermal progs and 00Z/12Z ensemble-based
GFS/ECMWF 850hpa temperature anomalies.
Wednesday will probably start out similar to today wrt low level
dryness and afternoon RH values devolving down into a "less than 20
percent" range, at least for portions of Fire Weather Zones 270,
271, 272, 273 and Big Stone/Traverse Counties in wc MN. By
afternoon, models are currently depicting a pocket of low level
moist air advecting down into the state, which would potentially
negate the RH criteria for a Red Flag Warning for a couple Fire
Weather zones in the CWA. At this point, 0.5km winds off the latest
RAP and the 12Z GFS/NAM/Canadian suggest the 25 mph gust criteria
could be met across northeast South Dakota Wednesday afternoon. Lots
of low predictability horizon on this moving window of potential, so
will defer to the next forecast shift to take another look at
.LONG TERM...(Thursday through Tuesday)
Issued at 147 PM CST Tue Nov 3 2020
Zonal flow aloft will transition to ridging just east of the CWA as
a western CONUS trough deepens late in the week/early in the
weekend. Suddenly the pattern becomes very high amplitude with north
south upper flow overhead Saturday and with a strong negatively
tilted trough lifting out of the Central Plains Sunday. The result is
the continued placement of milder air overhead, with 850mb
temperatures peaking Friday and Saturday around 20C which is over 2
standard deviations above climo. Blended guidance has underperformed
with the last few days of heat, so therefore went a few degrees
warmer Thursday through Saturday. After that, we are on the back
side of the upper trough and temperatures will be down a little below
normal with 850mb temperatures coming in around 10 below zero to
start off next week.
As for precipitation, most of the upper dynamics with the system
will be focused northwest of the CWA, and we are mostly in the dry
slot as the surface low moves up across the western Dakotas.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 532 PM CST Tue Nov 3 2020
VFR skies/vsbys are expected through tonight regionwide.
Area Forecast Discussion
National Weather Service Bismarck ND
936 PM CST Tue Nov 3 2020
Issued at 916 PM CST Tue Nov 3 2020
Clear skies continue across the region tonight. With dry air and
the clear skies temperatures have fallen rapidly in light wind
areas, into the upper 30s, while mixing keeping temperatures into
the lower 50s where winds are a little higher. So overnight low
temperatures will be a challenge. We generally lowered mins about
3 to 5 degrees tonight.
A dry cold front will move through the region Wednesday.
Reasonably good low level mixing behind the front should provide
a breezy to windy day Wednesday. Current winds in the forecast
look good, at 20 to 30 mph, and reflect the usually better mixing
RAP model. So no adjustments to winds or the forecast for
Wednesday at this time.
UPDATE Issued at 530 PM CST Tue Nov 3 2020
Winds have decoupled and mixing has ended across the region. Skies
will be clear across the region tonight.
We broke high temperature records this afternoon, at Bismarck (76
old record 70 in 1949) and Minot (73, old record 71 in 1904).
It will continue to be mild on Wednesday, with another breezy to
windy day in store. Current forecast looks good.
.SHORT TERM...(This evening through Wednesday)
Issued at 225 PM CST Tue Nov 3 2020
Continued mild weather highlights the short term period.
Currently, broad upper level ridging across the Northern Plains,
with an area of surface low pressure to our north associated with
an embedded mid level shortwave across far southern Canada. South
of this low a decent pressure gradient resides across western and
central ND today, with a steady westerly wind of 15 to 20 mph and
a few gusts occasional to 30 mph. Good mixing coupled with a dry
boundary layer has seen RH values from 15 to 20 percent, with
several sites in and out of RFW criteria. We opted earlier to
maintain the mid shift approach in mentioning near-critical fire
weather for today rather than hoist a headline, and will do the
same with this product issuance with only another 3 hours or so of
peak heating left for the day.
Otherwise for this afternoon, very mild and we have already
broken or tied record high temperatures for both Minot and
The warm air mass remains across the region for tonight, as the
surface low stays to our north. As we saw this morning,
temperatures will again be dependent on elevation and terrain
variability, with exposed hilltops likely remaining within a
shallow inversion layer while river and creek valleys radiate
efficiently in the dry air mass. The latest blend of models
reflected this for overnight lows well.
Embedded S/WV slides east across North Dakota on Wednesday, and
will result in another day of gusty west winds and slightly
cooler temperatures. Expect another day of near-critical fire
weather though overall humidity will be 5-10 percent higher. A
lower humidity forecast would put many areas near RFW criteria so
will keep an eye on this over the next few forecast cycles this
evening and tonight.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 225 PM CST Tue Nov 3 2020
The long term will see continued mild and dry weather through
Friday, followed by a significant pattern change over the weekend
into early next week.
Deterministic and ensemble models remain consistent in quasi-
zonal flow through Thursday, maintaining mild and dry weather. Our
flow transitions to more southwesterly late this work week as a
strong upper level low slams into the West Coast Thu night-
Friday. Cooler temperatures forecast but continued mild and dry.
Larger spread regarding high temperatures Sat/Sun continues in
members composing the NBM guidance as the upper low lifts north
across the Rockies and into the Northern Plains. Much uncertainty
remains in play with sfc pressure patterns, low level flow, and
thermal profiles of this system. More confidence in temperatures
materializes early next week in the wake of this storm system,
when the NBM spread is low with highs in the 20s to around 30
Monday and Tuesday.
The latest trend has been a drier and westward shift in the
heavier precipitation potential Sat night/Sunday, though much
uncertainty remains. It is likely we will see precipitation, just
how much and timing remains questionable with further shifts
possible, dry slot placement, and overall speed of the low. We
will message the higher confidence with the much colder
temperatures next week, and the higher uncertainty regarding
precipitation amounts and placement.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 530 PM CST Tue Nov 3 2020
Clear skies and VFR conditions are forecast through Wednesday.
There will be some wind shear KXWA-KMOT from 1200 feet to the
surface between 05-14z. See TAFs for details.
Area Forecast Discussion
National Weather Service Jacksonville FL
828 PM EST Tue Nov 3 2020
Clear skies at this time with large high pressure ridge dominating
the southeast U.S., with a weak sfc trough noted east of the
coast per latest analysis. The high will move east-northeast
through Wednesday morning with low level flow becoming more
easterly and ushering some low level moisture to a very dry
airmass. 00Z JAX sounding showed PWAT of only 0.46 inches.
Still cool tonight but not as cold as last night, with widespread
mins in the 40s inland and more so in the 50s toward the coast
with slight adjust down for mins. Only minor adjustment for sky
cover to delay clouds a bit as some stratocumulus will move
onshore early Wednesday morning. Still an outside chance of a
couple of light showers along the coast, per HRRR and GFS models,
south of Ponte Vedra Beach after about 4-5 AM.
No major changes except to bring seas up slightly along the
nearshore coastal waters rest of tonight. Winds mainly northeast-
east 10-15 kt rest of tonight.
.PREV DISCUSSION [648 PM EST]...
.Near Term.../through Wednesday/...
Strong high pressure will be north northeast of the region this
period. This pattern will lead to an increasingly moist and warmer
onshore flow. This will result in a milder night Tonight, and a near
normal day on Wednesday. Cloud cover will slowly increase from East
to West through the period, but well inland counties will experience
mainly clear skies. As moisture increases, chance for mainly coastal
showers increases as well.
.Short Term.../Wednesday night through Saturday/...
Surface high pressure will remain to the northeast through this
period, continuing the onshore flow pattern. Moist onshore flow will
result in shower chances through Friday. Models depict a potential
tropical system to the south Friday night into Saturday, which would
increase the potential for showers and storms.
Temperatures will trend a little above normal this period.
.Long Term.../Saturday night through Tuesday/...
A great deal of uncertainty in this forecast period, as longer range
models have little run to run or model to model consistency in
handling of potential tropical system.
At minimum with the surface high to the northeast a continued moist
onshore flow will yield cloud cover and precipitation chances. But,
if the system gets as close over the weekend as the 12z GFS depicts,
would have windy conditions and potential for heavy rain. At this
time, will continue to forecast above average precipitation chances
for the weekend, into early next week, with temperatures a little
[Through 00Z Thursday]
VFR conditions prevail, but an increase in clouds expected early
Wednesday as stratocumulus push into the area, with bases around
3-5 kft at times. A couple of showers will be possible along the
coast and included VCSH for SGJ by mid morning. Light to calm winds
tonight will become northeast around 6-12 kt on Wednesday.
High pressure will be northeast of the region through the weekend
into early next week, leading to a prolonged period of onshore flow.
Longer range models produce a great deal of uncertainty to the
forecast late in the weekend into early next week, due to handling
of a potential tropical system which may move into the region south
and southwest of area waters.
Rip Currents: SE GA: Moderate through Wednesday
NE FL: Moderate through Wednesday
.PRELIMINARY POINT TEMPS/POPS...
AMG 40 76 54 77 59 / 0 0 0 0 0
SSI 55 76 64 76 67 / 0 20 20 10 10
JAX 49 75 64 78 66 / 0 20 10 20 10
SGJ 59 76 67 79 69 / 20 20 20 20 20
GNV 50 77 59 80 63 / 0 10 10 10 10
OCF 52 78 61 82 65 / 0 10 10 10 10