Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/18/19
Area Forecast Discussion
National Weather Service State College PA
1150 PM EDT Sun Mar 17 2019
A weak area of low pressure will pass south of the state
tonight. It may produce a light coating of snow along the MD
border. Dry and mainly colder than normal temperatures are
expected for Mon- Tues. But, some light snow or rain is possible
Wednesday or Thursday and temperatures will be close to
normals. A slight cool down is expected for week`s end.
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Altocu/AltoStratus deck spreading in from the west this evening
across the southwest half of the CWA, while skies will remain
generally clear across the North-Central Mtns through 05Z and
far eastern zones through about 03Z.
Entrance region of a zonal upper level jet (110-115 KTS) along
the Mason-Dixon line, will support a very weak area of low
pressure at the SFC that will move just south of PA late
tonight/early Monday. Expect some very light snow to brush our
southern tier counties between 04Z-12Z Monday. Latest HREF and
RAP indicate that this forecast may even be too robust on the
snow, as both models indicate only spotty QPF of a few
hundredths of an inch south of the PA/MD border.
This forecast and slight southward trend to the precip is
reasonable based on very dry air in place across all of Central
PA, and the observation that the northern extent of any light
snow across Ohio this evening is situated to the south of the
mean 850-700 mb 285K Theta-E contour (which resides south of the
PA turnpike) with near neutral to slightly positive Theta-E
advection forecast in this layer overnight across the southwest
half of our CWA.
Places most likely to get a light dusting (less than an inch)
would be folks right along the MD border in Somerset County,
and mainly across the highest elevations. The temps in the
cloud layer are ripe for big dendrites, but it is very dry
underneath the 4-5kft cloud bottoms.
A few flurries are still possible as far north as I-80 in
Central PA and the Susq Valley, and also across the NW mtns, as
a separate sfc and upper level trough drops SE from the Glakes
and shifts the mean LLVL wind to the NW.
No accums are expected north of a JST-AOO-THV-LNS line.
Mins should be well below normals, with dewpoints only in the
single digits across much of the northern half of the area. The
srn half of the area will be closer to normal, with m-u20s
there, mainly thanks to the lower/thicker clouds. Wind goes
light/calm with a small nose of high pressure pretty much
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
The effects of the fast moving wave should pretty much be over
by morning, but some flurries/sprinkles could linger into mid-
aftn over the far SE, and some flurries are never out of the
question in the Laurels.
Northwesterly flow aloft will continue with temperatures
holding around 10 degrees below normal. Sfc wind will be light
in the morning, but pick up out of the NW through the day over
the Alleghenies as slightly cooler air aloft slides over the
area during the day. The cold advection will also lead to an
increase in low clouds and some flurries/sprinkles across the
north. There is just a small chc of an accum over the nrn mtns
in the aftn. However, daylight hours in mid-March are a very
difficult time to accum snow. Thus, PoPs will remain 30pct or
Mon night looks like we should clear out over most of the area,
but strato cu may linger over the NErn mtns. Mins a carbon copy
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Surface high pressure will move across Tuesday and Tuesday
night. Long-wave trough aloft will aid keeping temperatures
about 5 degrees below normal for this time of year and help
generate some afternoon clouds across the north. Surface high
center moves off the coast Wednesday. Southerly flow ahead of
next system along with March sun will warm temps to near normal.
Next system will move in Wednesday night with good chance for
rain and snow...snow mountains and colder locations north.
Thursday a short-wave rotates around upr level trough bringing a
chance for scattered light showers. Drier and warmer conditions
heading into and through the weekend. Near normal highs and lows
on Friday and Saturday with about a 10 degree jump on Sunday
climbing into the 60s many areas through central PA and across
the south. Warmer trend looks to last into the 8-14 day period.
Spring officially begins at 5:58PM on Wednesday 3/20.
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
Main focus in the near term forecast will be on low pressure
and associated light snow approaching from the Ohio Valley. All
model data keep the snow along and south of the Mason Dixon Line
late tonight and early Monday, with vfr conditions very likely
at the southern Pa airfields and nearly certain elsewhere.
High pressure building in from the Grt Lks should ensure
widespread VFR conditions and light winds Monday afternoon and
evening across all of central Pa.
Tue-Wed...No sig wx expected.
Thu...AM low cigs possible W Mtns.
Fri...AM low cigs/snow showers possible W Mtns.
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
221 PM PDT Sun Mar 17 2019
.SYNOPSIS...High pressure will aid in warm dry conditions across
the region through Monday. Wet and unsettled weather is expected
from Tuesday afternoon through late week.
.DISCUSSION...Visible satellite imagery shows Sunday morning
marine stratus burning off along the coast during Sunday
afternoon. The stratus has inhibited strong heating immediately
inland from the ocean. However, abundant sunshine across the
interior has aided in afternoon highs in the 60s and 70s. Another
warm day appears on tap for Monday...though uncertainty in highs
exists for coastal areas due to possible redevelopment of stratus
tonight that may linger through part of the day tomorrow.
Otherwise, an upper trough and associated weak surface frontal
boundary will enter the area during Tuesday afternoon and evening.
Light showers will become probable, with rain lingering through
Wednesday night. A brief period of post-trough drying will be
possible Thursday afternoon before another storm system approaches
from the west Thursday night into Friday. Model guidance indicates
rainfall will be slightly heavier with the Friday system...though
hydrologic impacts are expected to be minor to non-existent at
this time. After Friday, slightly cooler temperatures and snow
levels falling to near 3500 feet are forecast to spread across
the region during the weekend.
.AVIATION...Areas of stratus and fog have been lingering along
the immediate shoreline this afternoon. Shallow marine layer
conditions may continue to erode this evening, primarily north of
Cape Mendo where the marine inversion has been descending
according to the ACV profiler. NAM profiles indicate drier
boundary layer conditions this evening and tonight, while the HRRR
was not quite as dry. Also, visible satellite imagery showed an
eddy spinning up in the stratus field south of Cape Mendocino.
Southerly winds right along the coastline may draw some of this
stratus northward into KACV later tonight. Forecast confidence
that VFR conditions this afternoon will be replaced with
persistent IFR or LIFR conditions at KACV and KCEC for tonight
remains low. Fortunately for KUKI, the forecast is much more
simple with VFR holding through the forecast period.
.MARINE...Winds Monday will gradually switch to the south, and
will increase to around 15 or 20 kt during the day Tuesday. This
will likely generate some modest steeper seas in addition to the
arrival of yet another westerly swell, resulting in combined seas
that may top out in the 10 to 12 ft range, particularly across the
southern and outer waters where winds will be slightly stronger.
Winds will weaken Wednesday and Thursday, but yet another
reinforcing swell will move through the waters Thursday, followed
by a round of stronger southerlies Friday. As a result, seas
Friday are likely to become a bit more hazardous, perhaps with
combined wave heights in the 12 to 15 ft range. /BRC
.BEACH HAZARDS...A westerly long period swell will aid in a
sneaker wave threat along area beaches through this evening.
Beach-goers should use caution and keep a safe distance from the
surf zone, as waves may suddenly wash much farther up the beach
than expected after several minutes of relatively smaller waves.
Remember that appearances can be deceiving, particularly in
situations like this when the ocean surface appears relatively
smooth and free of messier wind waves. /BRC
CA...Beach Hazards Statement until 9 PM PDT this evening for
NORTHWEST CALIFORNIA COASTAL WATERS...None.
Visit us at http://www.weather.gov/eureka
Follow us on Facebook and Twitter at:
For forecast zone information
see the forecast zone map online:
Area Forecast Discussion
National Weather Service Hastings NE
659 PM CDT Sun Mar 17 2019
.SHORT TERM...(This evening through Monday)
Issued at 209 PM CDT Sun Mar 17 2019
A weak upper level disturbance and associated cool front across
the Dakotas is expected to drop south across the local area
tonight...with the last few runs of the HRRR and RAP trying to
generate some light shower activity with its passage during the
evening hours. With the focus of this disturbance to our
east...felt that confidence of any appreciable precipitation
locally was low...and decided only instead to increase cloud
cover along with some silent pops through the evening hours.
Otherwise...at the surface...expect a ridge of high pressure to
slide south across the local area overnight through Monday
afternoon behind the aforementioned front...providing a slightly
cooler airmass and light winds through tomorrow afternoon. At the
same time...expect cloud cover to begin to increase from the
northwest ahead of the next disturbance tomorrow...with a very
small chance of some light rainfall west of highway 183 late in
.LONG TERM...(Monday night through Sunday)
Issued at 209 PM CDT Sun Mar 17 2019
An upper level disturbance visible in settle in across the
northern Rockies this afternoon will cross the local area Monday
night through Tuesday...bringing the next potential round of
precipitation to much of the local area. While moisture is not
particularly robust with this system...any precipitation is
unwelcome for most folks across our forecast area at this time.
That said...models have trended...and continue to trend a bit
further north and wetter with this system for the Monday
night/Tuesday time frame...and precipitation totals have
correspondingly increased about a tenth of an inch across the
heart of the local area. At the same time...temperatures behind
tonights cold front have come down a couple of degrees...and the
chance for some accumulating snow has increased. While the snow
will not stick around long...a band of snow is progged to set up
across south central Nebraska overnight Monday into early Tuesday
morning...potentially dropping from 1 to 3 inches of wet, slushy
Thereafter...an upper level ridge will transition across the
plains for the middle portion of the week, but a change in the
pattern appears to be in store for late week as the first of
several disturbances brings a chance of precipitation as early as
Thursday afternoon...with off and on chances for additional
precipitation through at least next Sunday, and possibly beyond.
At this time, did not add thunderstorms to the forecast for the
time being, but instability does increase across the region
Saturday, which looks like the best chance for thunder across the
local area in the current forecast period.
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday)
Issued at 652 PM CDT Sun Mar 17 2019
Light west wind should eventually turn more north as some mid-
level sky cover approaches as a surface high moves in, keeping
wind speeds on the light side.
Area Forecast Discussion
National Weather Service Jacksonville FL
954 PM EDT Sun Mar 17 2019
.UPDATE...A surface wave well offshore will move slowly
east tonight allowing for cooler and drier air to gradually
move into the area. 00Z HRRR suggests clouds will gradually
lift most areas overnite but lower clouds persisting across the
far southern counties. A few showers will also be possible there
as well. Temps appear on track with lows in the 40s most areas
except 50s along the Ne Fl coast.
.AVIATION...Prevailing VFR cigs tonight for most terminals.
Lingering MVFR cigs at GNV til around 03Z and at SGJ til
.MARINE...Surface wave well offshore will slowly move east
tonight. The gradient between the wave and high pressure
to the northwest will produce exercise caution across all
of the waters.
Rip Currents: A high risk is anticipated for the Ne Fl beaches
and a moderate risk for the Se Ga beaches on Monday.
.PRELIMINARY POINT TEMPS/POPS...
AMG 41 67 44 63 / 0 0 0 0
SSI 47 67 51 60 / 0 10 0 0
JAX 47 69 51 64 / 0 10 0 10
SGJ 53 66 54 64 / 20 10 0 20
GNV 46 70 49 66 / 20 10 0 10
OCF 50 70 50 68 / 30 10 10 30
Area Forecast Discussion
National Weather Service Key West FL
1042 PM EDT Sun Mar 17 2019
.SHORT TERM...(Tonight through Tuesday)
A period of rain (sometimes heavy) and wind is coming up, with the
worst weather coming from late Monday night through Tuesday.
A shallow cold front is currently making its way down the southern
Florida Peninsula, with surface obs showing it along a line from
near Naples to Palm Beach. The front will continue to ease south
tonight, passing south through the Keys before sunrise on Monday.
It should be accompanied by little or no rain, but low clouds may
fill in behind the front and set up an uncharacteristically gray
start to Monday morning. The front will turn up stationary near
the north coast of Cuba on Monday afternoon.
Meanwhile, a distinct subtropical jet stream across northern
Mexico and the Gulf will scoot the well-formed shortwave now
making its way across the northwest Mexican state of Sonora into
the western Gulf of Mexico on Monday night and Tuesday morning.
As it moves east across the Gulf, its forcing will really energize
the front to our south. Low pressure will first develop along the
portion of the front west of the Yucatan on Monday, with the low
pressure wave moving by along the front just to our south on
Tuesday PM. Here on the north side of the front, this will bring
windy northeast winds. Looking for lots of warm advection lift up
and over the shallow cool dome, given strong southwest flow
aloft. Favorable dynamics and lift will maximize on Tue afternoon
as the favored left-exit region of the subtropical jet passes near
the Keys, concurrent with the favored right-entrance region of a
departing jet streak off the Carolina coast. With all of this lift
acting on a juicy air mass with integrated Precipitable Water
values of 1.75"-2.00", will be looking at heavy rain potential of
1"-1.5" over the Keys on Monday, with a slight chance of rain
exceeding 2" over the Upper Keys.
.LONG TERM...(Tuesday night through Sunday)
From Previous Discussion: The mid-upper level trough axis will
slide east of the Keys Tuesday night. Rain chances will decrease
sharply, followed by a welcomed few days of cooler than normal
temperatures. Model guidance remains mixed for rain chances
through the extended. We have therefore used a blend, which has
consequently raised chances to 20% for much of the extended. No
other changes at this time.
A cold front will slip into the coastal waters of the
Florida Keys late tonight. Light and gentle northerly breezes
will turn to the northeast and gradually freshen late tonight and
Monday as the front stalls out near the northern Cuban coastline.
Fresh to strong northeast breezes are expected Monday night
through Tuesday night, as low pressure moves eastward along the
stalled front. Northeast breezes will peak Tuesday evening.
Northeast breezes will slacken somewhat Wednesday and Wednesday
Surface winds will veer more northeasterly overnight at EYW and
MTH. Around 09z-10z on Monday morning, the HRRR shows a small
surge in NE wind as a cold front reaches the terminals. This
should be followed by some low clouds with bases of 010-015 off
the Florida Peninsula behind the front. BKN cigs that low may
last for only a couple hours, if they develop at all. However,
model time- height sections shows rich boundary layer moisture
continuing until well into Monday afternoon, so at least SCT
coverage of clouds below 020 will continue at times, with cigs at
or below 030 being advertised in statistical guidance through
Monday evening and beyond.
Visit us on the web at weather.gov/key
Follow us on Facebook and Twitter at:
Area Forecast Discussion
National Weather Service San Diego CA
223 PM PDT Sun Mar 17 2019
Temperatures will remain above average under mostly clear skies
through Monday ahead of a Pacific storm system arriving midweek.
Patchy low clouds and fog may return as early as Monday morning
along the coast, though more likely Tuesday morning as a coastal
eddy develops. Conditions will cool as onshore winds increase this
week. Scattered showers are expected Tuesday night through
Thursday with the best chance on Wednesday. A few thunderstorms
are even possible Wednesday through Thursday as colder air aloft
moves in from the north. A weak upper ridge will build in
briefly on Friday ahead of another system passing to the north
this weekend, but the tail end could affect Southern California
for the potential of additional showers, mainly on Saturday.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
GOES-17 Satellite imagery shows a clear sky across the region. No
signs of any low clouds developing. WRF is showing a coastal eddy
developing overnight with fog or low clouds moving in along the
coast, but this model is often a day too soon. HRRR surface
visibility is above 10 miles overnight. So while patchy fog or low
clouds is possible, it is of low confidence. Believe most of the
area will be clear tonight through Monday. Monday night stands a
better chance of fog or low clouds near the coast.
Temperatures have really warmed up today with widespread 70s and
even low-mid 80s inland. The immediate coast is in the 60s as a
sea breeze has developed and blowing in colder air off the 57
degree ocean temps. Today is the peak of the warmth. Conditions
will gradually cool over the next few days as onshore flow takes
The next Pacific system is poised to arrive by Tuesday night and
move across the area Wednesday-Thursday. Strength of this system
is in question. The operational GFS and GFS ensemble mean continues
with higher heights compared to the ECMWF, which digs the closed
low further south and overhead by Thursday. Given this and
uncertainties with this, followed a blended approach. As colder
air moves in overhead Wed-Thu, instability will increase to allow
for the potential of isolated thunderstorms to develop. Added this
into the forecast.
Precipitation amounts continue to look to be rather tame as
the transport of moisture with this system is in a diminishing
process as the moist plume moves over the area. Still, it is
looking like 0.25-0.50" will fall at most locales west of the
mountains, 0.50-1.00" along the coastal mountain slopes to
0.05-0.15" over the deserts. Maximum hourly rates to 0.50"/hr is
forecast in isolated heavier showers or tstorms that develop.
Snow levels looks to be at near 6000 FT on Wednesday then down to
about 5500 FT on Thursday. Snowfall amount of 2-4" are possible
at ski resort level with heavier snow of 6"+ above 8000 FT.
Southwest winds will become strong along the deserts slopes
Tuesday night-Wednesday with gusts to 50+ mph possible.
The system will move away from the area Thursday night with weak
upper ridging building in on Friday. However, GFS ensembles show
the southern extent of another storm system affecting SoCal this
weekend, right now with a Saturday timing. This looks to bring
some more showers to the area with low precipitation amounts
expected as this looks weaker.
That system moves away Sunday with tranquil weather following in
its wake next Mon-Tue. GEFS shows lowering heights associated
with yet another shortwave/storm system moving in from the west
and into SoCal Wed-Thu, March 27-28. An active weather pattern
172005Z...As luck would have it, we will see mostly clear skies with
unrestricted vis through early this evening. Small chance of low
clouds with bases 700-1000 ft MSL developing along the coast after
08Z Monday, with low to moderate confidence. SCT cigs near 1000 ft
MSL forecasted to continue for much of Monday morning for coastal
TAF sites. Inland areas will see mostly fair skies throughout the
No hazardous marine weather is expected through Tuesday night. A
Pacific storm may bring periods of showers, building seas, and gusty
west winds Wednesday through early Friday.
High surf of 6-9 ft in portions of San Diego County possible
Wednesday through Thursday due to a building west swell of 7-9 ft at
15-17 sec from 280 degrees. Elevated surf of 3-6 ft is possible in
Orange County. High rip current risk will occur Wednesday through
Thursday. Swell and surf will subside on Friday.