Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/28/20
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
835 PM MST Fri Nov 27 2020
A quick update to the overnight forecast package to add in mention of
patchy fog and freezing fog. Did massage PoPs a bit to show a
smoother transition of precipitation over the eastern plains in the
11pm to 2am timeframe. Where and when fog/freezing fog develops will
remain the most uncertain part of the forecast into Saturday morning.
The latest hi-res models do seem to be initializing better with the
last couple of runs, depicting precipitation within a wrap-around
section over central portions of the state this hour, not making it
as far north as earlier runs. These hi-res solutions do hint that
snow west of the Rio Grande will come to an end just between midnight
to 2am, so Winter Weather Advisories there may be cancelled early.
Latest zones forecast package is out.
.PREV DISCUSSION...448 PM MST Fri Nov 27 2020...
00Z TAF CYCLE
A wintry mix of precipitation continues over central NM and the Rio
Grande Valley from KGNT to KSXU and from KONM to KSKX. Snow at this
hour is still limited to western TAF locations and over the
mountains, but temperatures and snow levels are already falling and
should fall to valley floors by 0030Z to 0130Z. TAFs at KABQ-KAEG-KSAF
reflect this transition from -rasn to -sn in the next hour with vis
restrictions becoming more common thereafter until precipitation
stops during the 09Z-12Z timeframe. Afterward, precipitation shifts
more over eastern NM as the core of the low moves eastward. The most
uncertain part of the forecast is the development of IFR/LIFR cigs
and fzfg once precipitation ends. TAF amds for fg/fzfg throughout
the night will be likely, notably for KGUP and KLVS. Lastly, the east
canyon winds through KABQ and KSAF are still expected to subside
over the next 2 to 4 hours.
.PREV DISCUSSION...250 PM MST Fri Nov 27 2020...
A storm system will continue to track eastward across New Mexico
tonight and Saturday, and light precipitation will spread into
central and eastern portions of the state. Highest additional
accumulations of 3 to 6 inches are expected along the central
mountain chain above 7,500 feet with lesser amounts expected for
lower elevations. Another cold front early Sunday will result in
gusty northerly winds across eastern New Mexico. Temperatures will
gradually warm Sunday and Monday under quieter weather conditions.
However, a highly unsettled weather pattern takes shape by mid-week
which may result in more mountain snow and colder temperatures for
SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)...
The wintry storm system isn`t going to be very well behaved tonight
and Saturday before it exits. Looks as if the center may pass
between Socorro and T-or-C which is apparently farther south than
previously anticipated. Would not be surprised to see it go even
farther south based on the mid/high level water vapor imagery
indicating high pressure building over the northern Rockies and
plains. It`s also slower moving, with a good deal of wrap around
precipitation depicted, possibly impacting the Santa Fe and
Albuquerque areas, with the HRRR indicating the greater snow amounts
over western Valencia county overnight. Hoisted a winter weather
advisory for both of these zones as the east wind tapers off and
becomes northerly this evening. As precipitation migrates into the
plains, models point toward southern Union, portions of Quay, Curry,
De Baca and Guadalupe counties being impacted with 1-3 inches
although the HRRR and NAM12 indicate southern Union county would be
the focus area. Therefore the winter weather advisory was also
expanded into most of these areas with snow commencing later tonight
and persisting into Saturday morning. As well, pops have been
increased over eastern NM for Saturday. Interesting to note, and not
sure if this is indicative of a monkey wrench but an area of 4000-
6000 ft ceilings has been expanding during the day over southeast NM
and into far southeast Lincoln county as well as closing in on
Roswell attm. Overall forecast storm total snow amounts may be on
the light side, so look for updates.
Temperatures Saturday and Saturday night will be near to below
LONG TERM...(SUNDAY THROUGH FRIDAY)...
A strong backdoor cold front will surge through eastern NM early
Sunday morning and push westward to the Continental Divide by early
afternoon. A strengthening surface pressure gradient along the front
plus increased 700mb winds will result in gusty northerly winds
across the eastern plains - particularly near the NM/TX/OK borders.
Guidance continues to increase wind speeds in this area, and brief
Wind Advisory speeds may be possible in the Clayton area. Another
east canyon wind in central valleys also appears likely by mid-day
Sunday, but it only expected to be modest with gusts near 20 to 25
mph. Otherwise, northwest flow on Sunday will lead to rising
temperatures for most with the exception being across the northeast
behind the front.
Northwest flow aloft continues on Monday, but a highly amplified
pattern will start to set up over the CONUS. At least one more quiet
day is expected for the Land of Enchantment on Monday under
northwest flow although pressure heights do begin to fall in response
to the amplifying pattern. Thus, temperatures do fall a few degrees
for most across central and western NM while a lee-side low will
allow temperatures to warm several degrees across the northeast. What
follows after Monday is a complex pattern with little forecast
confidence at this time. Operational models indicate a strong storm
system from the Gulf of Alaska diving southward into the central
Rockies on Tuesday which seems slightly faster than models were
portraying 24 hours ago. Details on the low`s track and potential
impacts to the area are fuzzy at best. The latest run of the ECMWF
has the low diving straight southward through the state. The GFS, and
to some extent the Canadian, show the low clipping northeastern NM
Wednesday with another low right behind it on Thursday.
Unfortunately, ensembles as well as little model run-to-run
consistency don`t offer much guidance in any solution at the moment.
The one thing that has seemed to be consistent is that regardless of
the details, moisture does look to be limited for widespread/heavy
precipitation. Kept PoPs next week fairly close to the NBM with
meager chances mostly across the northern half of the CWA. The bigger
impact with this amplified pattern will more than likely be much
colder temperatures. Confidence is much higher that temperatures will
drop to well below normal Wednesday through Friday. Stay tuned.
Upper low to move slowly over central New Mexico during the next 24
hours bringing small to moderate amounts of accumulating snow to
much of the higher terrain of northern and central New Mexico as
well as portions of the valleys and plains. Cooler than normal
temperatures through the weekend and much of next week are forecast.
Widespread poor ventilation over much of the region for the next 7
days, and especially Saturday and Monday. Sunday and Monday appear
dry but very unsettled and colder than normal weather is possible
Winter Weather Advisory until 4 AM MST Saturday for the following
Winter Weather Advisory until 9 AM MST Saturday for the following
Winter Weather Advisory until 9 AM MST Saturday for the following
Area Forecast Discussion
National Weather Service Caribou ME
918 PM EST Fri Nov 27 2020
A weak low will move along the Downeast coast overnight.
A cold front will cross the region Saturday. High pressure will
cross the region Sunday. Strong low pressure will approach from
the southwest later Monday then track well west of the area
Tuesday. An occluded front will cross the region later Tuesday.
Low pressure will remain northwest of the region Wednesday.
.NEAR TERM /THROUGH SATURDAY/...
9:18 PM Update: Models did not do a great job with the showers
that have blossomed across the southern half of the FA this
evening. The latest 01Z HRRR seems to have a reasonable handle
on the current coverage of the showers. Observations have
indicated a few spots that have picked up from 0.01-0.05" during
the past 2 hours. Made some adjustments to increase the PoPs
and QPF across southern portions of the FA. Drizzle has been
observed here at the WFO in Caribou this evening, and based on
earlier reports and with continued snow melt there will likely
be some fog the remainder of the night.
Weak low pressure will move along the Downeast coast tonight
with a chance of rain showers. Weak high pressure will cross the
remainder of the region, with lingering low level moisture
supporting mostly cloudy skies. An approaching cold front and
upper level disturbance could also bring isolated/scattered snow
showers to northern areas late. Will also have patchy fog across
the region tonight through early Saturday. The upper level
disturbance and cold front cross the region Saturday with
scattered rain/snow showers across the north and mountains.
Across Downeast areas, expect mostly cloudy skies with still
isolated/scattered showers in the morning. Partly sunny skies
are then expected Downeast during the afternoon. Low
temperatures tonight will range from around 30 to the lower 30s
north, to the mid to upper 30s Downeast. High temperatures
Saturday will range from the upper 30s north, to the mid 40s
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
Short wave moves east Saturday night. The exiting system could
produce a few snow showers across the north during the evening
followed by partial clearing late. Low temperatures will range from
the mid to upper 20s north and central areas to near 30 toward the
Surface and upper ridge builds in on Sunday with fair weather
and unseasonably mild temperatures. Highs on Sunday will range
from the upper 30s to near 40 north and low to mid 40s Downeast.
Clouds increase Sunday night in advance of low pressure tracking up
from the southwest. Upper level energy moves northeast from the
southwestern states combining with upper level energy moving out of
the Great Lakes region on Monday. This results in deep surface low
developing to our southwest during Monday. This will result in
thickening clouds early Monday with rain developing from west to
east Monday afternoon. Highs on Monday well above normal for this
time of year.
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Widespread rain event will affect the region Monday night into
Tuesday. A and warm deep layered southerly flow is expected during
that time frame with good moisture transport expected. Noted that
the latest WPC day 4-5 QPF outlook is indicating the potential for
3+ inch rainfall for portions of central and Downeast areas of
our CWA. Still a few days out, but this obviously has the
potential to be significant rainfall event for much of our
region. Another factor will be the potential for gusty south
winds across Downeast areas with 925MB winds of 50 kt expected
The steadier rain begins to taper to showers later Tuesday and
Tuesday evening. Cooler weather with the chance for rain/snow
showers return for late week.
Temperatures will be well above normal on Tuesday and continued
above normal on Wednesday. Expect temperatures by the end of
next week to be near normal Thursday and Friday.
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: VFR/MVFR conditions early tonight will lower to
IFR/LIFR levels overnight, although confidence on the lower
ceilings is highest across the far north at KFVE. Isolated snow
showers are possible across northern areas later tonight.
Scattered rain showers are expected Downeast. Fog is likely
across the entire region tonight through early Saturday.
IFR/LIFR conditions are expected across the region early
Saturday. VFR/MVFR conditions are then expected Saturday
afternoon. Scattered rain/snow showers are expected across the
north and mountains Saturday. Isolated/scattered showers are
possible Downeast early Saturday.
Sat Night...MVFR possible in evening snow showers mainly north,
otherwise VFR. SW Wind 5 to 10 kt.
Sun-Sun Night...VFR. SW wind 5 to 10 kt.
Mon...VFR, then possible MVFR/IFR in developing rain form W-E.
Mon night-Tue...Widespread IFR/LIFR in locally heavy rainfall. Gusty
Tue-night...IFR/MVFR in rain showers.
NEAR TERM: Winds/seas will remain below small craft advisory
levels tonight through Saturday. Visibilities will be reduced in
rain showers and patchy fog tonight through early Saturday.
SHORT TERM: Winds/seas should remain below SCA levels Sat night thru
Sun Night, then increase to SCA levels Mon. Gale conditions are
possible Mon night with seas building to 10-15 ft. SCA
conditions are likely on Tue.
We are forecasting a high of 54F on Tuesday, December 1st in
Caribou. The record high for December 1st is 48F, set in 1991.
The last time we observed a high of 54F or warmer during the
month of December was on December 14, 2010, when the high was
57F. The all-time record high for the month of December is 58F,
set on December 12, 1950.
Area Forecast Discussion
National Weather Service Jacksonville FL
929 PM EST Fri Nov 27 2020
...PATCHY DENSE FOG TONIGHT...
A weak front was across nearly stationary over southeast GA but is
expected to slowly shift south through Saturday morning. Shower
activity has diminished considerable since the afternoon hours as
the airmass has stabilized. With light winds, seasonably high
PWAT values of about 1.5 inches, and subsequent dewpoints in the
mid- upper 60s, low clouds and some developing fog are expected
for a good portion of the night so have increased coverage with
the evening update. Some dense fog is expected at times. Still
tracking a disturbance upstream of the region over AL and the FL
panhandle, producing areas to widespread shower activity and
isolated embedded thunderstorms. This activity expected to push
into the forecast area by about 4 AM or so. Have bumped up POPs a
bit for early Saturday for this system based on radar trends and
HRRR model guidance. No change made to the low temps in the lower
to mid 60s tonight with skies becoming mostly cloudy after
midnight for most areas.
Current forecast was on tack with light winds and seas at or below
4 ft rest of tonight. Introduced some patchy fog for the
nearshore waters and included a marine weather statement for the
fog. It is possible fog may disperse a bit after about 4 or 5 AM
Saturday as a cold frontal boundary pushes into the region.
.PREV DISCUSSION [656 PM EST]...
.NEAR TERM [Through Tonight]...
Scattered low-top showers have broken out this afternoon across
southeast Georgia and the Suwannee Valley as a quasi-stationary
front slowly advances southward across southern GA. Meager
instability and a strong mid-level inversion will effectively limit
any chance for thunderstorms through the rest of the afternoon and
evening. The front will continue to drift south tonight as high
pressure over central Florida breaks down amd builds into the Ohio
After a brief break in shower activity this evening, another round
is expected overnight across southeastern GA. An upper trough axis
will pivot across the Mid Atlantic states and overtop the stationary
front tonight, providing sufficient lift through early Saturday.
Isolated areas of inland southeast Georgia could receive up to an 1"
of rain by sunrise on Saturday.
In addition to the rain overnight, patchy fog will likely develop
along the nearly stalled frontal zone but away from the shower
activity. Best chances for fog development will be inland northeast
Florida west of the I-95 corridor. Locally dense fog will be
possible in area through Saturday morning.
.SHORT TERM [Saturday Through Sunday Night]...
The quasi-stationary front will make more southward progress on
Saturday as upper trough axis pivots into the western Atlantic and
surface high pressure builds to the northwest. Scant instability and
considerable cloudiness on Saturday should limit potential for
widespread shower activity along the frontal zone. An upper cutoff
low over west texas will spawn a surface cyclone in the northwestern
GOMEX Sunday. This will lift the quasi-stationary frontal zone
northward as a warm front, warm-sectoring the area. Mass response
from deepening surface low to the west will increase bulk and low-
level shear parameters, however very weak instability will be a
limiting factor. If enough instability is generated and convection
can initiate successfully, strong to severe storms will be possible
Saturday afternoon and evening ahead of the cold front. Run-to-run
model consistency has fallen of a bit regarding the timing of the
attendant cold front which now looks to pass through Monday
morning/afternoon rater than late Sunday/early Monday. Temps will
remain above average through the weekend.
.LONG TERM [Monday Through Friday]...
Potent cold front will track eastward across the region on Monday,
bringing drier air, breezy conditions, and significant drop in
temperatures through early next week.
As the front passes through Monday a squall line of showers and t-
storms will precede it. Temperatures will drop substantially
from Monday to Tuesday with highs on Tuesday forecast to stay in
the 50s. Lows on Tuesday morning will dip into the mid 30s across
southeast Georgia and Suwanee Valley while the upper 30s/low 40s
are likely across along the coast and north-central Florida. As
the post-frontal northerly breezes lighten morning lows will drop
further Wednesday morning with readings at or below freezing
inland and to the upper 30s along the coast. Temps will gradually
rebound through the end of the week as surface high shifts
offshore and another low pressure system and reinforcing cold
front develops to our west. Rain chances will increase with the
approach of the late week cold front.
[Through 00Z Sunday]
A weak cold front will sag southward over the area late tonight
and early Saturday. This front and weak synoptic lift will result
in deteriorating conditions overnight with low clouds and
prospects for low visibility. Shower activity looks fairly light
at this time. Already seeing a few places reporting low stratus
below 1 kft this evening along the coast around Mayport,
Fernandina, and St Simons Island. Continued to trend cigs down
tonight with just a bit quicker lowering of vsby and cigs by about
the 03Z-08Z time frame for CRG, JAX, VQQ, and SSI with IFR and
LIFR. A chance of VLIFR late tonight for these sites. A slow
ceiling increase through daybreak Saturday with VCSH and SHRA
through midday under shifting winds, due to cold frontal passage,
around to north or northeast at SSI early Saturday morning and
probably rest of the TAFs developing after 15Z-18Z Saturday.
Rainfall is expected through the weekend ahead of a developing low
pressure system. However, rainfall will be short-lived and is not
expected to result in any substantial hydrologic concerns.
.PRELIMINARY POINT TEMPS/POPS...
AMG 59 68 56 69 56 / 70 80 30 60 70
SSI 62 69 61 72 62 / 50 70 20 50 50
JAX 62 72 61 74 62 / 50 60 30 40 40
SGJ 64 76 63 77 65 / 10 50 30 20 30
GNV 62 75 61 77 62 / 20 50 20 20 50
OCF 62 79 63 79 65 / 10 40 10 10 40