Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/31/19
AREA FORECAST DISCUSSION
National Weather Service Cleveland OH
1038 PM EDT Sat Mar 30 2019
.SYNOPSIS...
A cold front across the area will continue to push southeast
tonight, as a mid level disturbance tracks northeast along the
front. A stronger upper trough will push east across the
southern Great Lakes on Sunday. High pressure will build east
through the southern Great Lakes and Ohio valley Sunday night.
Ridging will remain in place across the local area through
midweek.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
Issued a Winter Weather Advisory for portions of the Greater
Cleveland area where we are trying to pinpoint higher snowfall
totals. In particular, we are keying in on the area of heavier
precipitation moving northeast out of Central Ohio. This is
paralleling the rain/snow line meaning some areas will see heavy
snow to the north and others moderate to heavy rain. Northwest
Ohio and areas extending northeast along the lakeshore towards
Cleveland have already transitioned to snow and heavy snowfall
rates of 1 to 2 inches per hour are possible through 1 AM.
Surrounding areas including the Mansfield/Ashland areas and
points extending up the lakeshore can also expect several inches
but not as much as Cleveland and Vicinity. The transition will
be a little slower towards Erie, PA and parts of western Ohio where
the air remains warmer aloft and this may cut into snowfall
totals. Models also hinting at some increased lift and
convergence downwind of the lakeshore which could contribute to
some locally higher amounts. As for pure lake effect, we will
not be cold enough until late Sunday morning but we do hold onto
a cyclonic flow which contributes to the enhancement. Not out
of the question that the Advisory may need to be expanded in
time or area and will continue to monitor trends.
Previous discussion...
Challenging near term forecast this evening as a cold front
bisecting the region, generally along the I-71 corridor this
afternoon, sinks southeast across the area. A very potent mid
level vort max over MO with an attendant coupled upper jet
feature will lift northeast along/behind the surface front
through the area tonight. A secondary mid level PV anomaly over
MN will dig southeast towards the area tonight, moving east
through the area on Sunday. High pressure will build east
through the Ohio valley late Sunday through Sunday night.
Through 00Z, a swath of widespread precipitation will work
northeast across the area. This will provide moderate to at
times heavy rain, especially along and south of the surface
boundary. A few rumbles of thunder isn`t out of the question
either given the strong upper dynamics, upstream lightning
across the Ohio valley, and hi-res guidance indicating some
weak instability working into the far southeast part of the CWA,
mainly south of a Mt. Vernon to Youngstown line. Total rainfall
amounts exceeding an inch to an inch and a half cannot be ruled
out.
The bigger question will be the transition to snow behind the
front, as robust CAA works through the area and heavy precip
aids in diabatically cooling the layer. The gamut of mid range
and hi res guidance indicates the potential for impressive
upward motion coinciding with the transition from rain to snow.
Model soundings show saturation through the mid into the upper
levels, with robust lift in the mid levels. Where this heavy
precip is occurring and the boundary layer cools to below
freezing through the layer, a corridor of heavy snow is expected
to work east northeast across the area sometime between 03Z and
08Z. Guidance has been back and forth with the details, but the
consensus is the heavier burst of precip will occur somewhere
from Mansfield northeast into the primary snowbelt, especially
across the higher terrain. Lake enhancement will aid in the snow
across the snow belt this evening, with a gradual transition to
primarily lake effect/upslope snow Sunday morning, before
gradually ending through Sunday night.
Now, there are several questions that dictate overall snowfall
number overnight into Sunday. The main question is where will
the heaviest precip coincide with the earliest transition to
mainly snow? Also, how long will the heavy rates persist in any
given location? To compound the issues of the timing of the
changeover, surface temperatures will be marginally near or
slightly above freezing as the snow starts. Currently thinking
there will be heavy enough snowfall rates, a brief 1 to 3 hour
window of 1 to 2 inch per hour rates, to overcome the warm
ground/pavement temperatures and the marginal surface air
temperatures to allow for some accumulating snowfall. There are
many uncertainties that have led to only a slight uptick in
snowfall amounts across the area from the previous forecast.
Many hi-res guidance suites are painting solid advisory to even
warning snowfall accumulations, however it is hard to say how
much of an impact the warm ground/pavement will lead to overall
compaction of the higher ratio snowfall shortly after the heavy
precipitation ends. Also, somewhat concerned with a mid level
dry slot noted moving into MO with the mid level impulse that
could bring an abrupt end to the widespread synoptic post
frontal precipitation. The latest HRRR runs are even picking up
on this feature. Nevertheless, have went with a general 2-4 inch
snowfall forecast from Mid-Ohio through the primary snow belt,
with some local 5 inch amounts across the higher terrain of the
snow belt, with the addition of lingering lake effect through
the day on Sunday. Have decided to hold off on any headlines
at this point, but trends will be monitored this evening and if
the changeover looks to be happening sooner and the dry slot
remains a decent distance away from the local area, there will
likely need to be an upward adjustment in snowfall amounts and
likely headlines. However, the confidence isn`t there right
now.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Broad troughiness will take place over much of the United States
Monday through Tuesday. Although a weak ridge will extend north
across the forecast area Monday allowing surface high pressure to
build east across the Tennessee and Ohio Valleys. The surface high
will then move off the east coast by Monday night. An upper level
ridge will begin to build east into the eastern United States by
Tuesday night. Fair weather will be the rule during this period as
moisture streaming east across the Great Lakes Tuesday and Tuesday
night should remain just north of the area in associating with a
fast moving upper level positive vorticity maximum. Cold air
advection expected during the early part of the week will begin to
retreat and move east of the area Monday and Tuesday. So, warming
temperatures are expected with highs on Monday in the lower to
middle 40s followed by highs Tuesday upper 40s northeast to middle
50s elsewhere. Lows Monday night in the 20s warming to the middle to
upper 30s Tuesday night.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Broad upper level ridge will move east of the area Wednesday into
Thursday allowing potent shortwave trough to race east across the
Great Lakes region Thursday night and become negatively tilted.
Another ridge will begin to build east over the area by Saturday.
Surface high pressure firmly entrenched from the Georgia coast north
to the Great Lakes will move east off the Eastern Seaboard Thursday
night and Friday. As upper level trough becomes negatively tilted
Thursday night, surface low pressure will move east out of the
central Rockies and then deepen as it moves northeast into the
central Great Lakes by Friday night. The storm system will tap into
some Gulf of Mexico moisture as it moves into the area. This system
will bring another round of rain to the forecast area. Rainfall
amounts between 0.50" and 0.75" is possible with this system. Rain
will pull out to the east late Friday night into Saturday.
A gradual warming trend will take place as warm air advection occurs
behind the high pressure moving off the east coast and in advance of
the low pressure moving into the Great Lakes. Will stay
conservative on high temperatures during this period due to the
advancing cloud cover and precipitation chances holding temperatures
down a tad.
&&
.AVIATION /00Z Sunday THROUGH Thursday/...
A cold front extends from near CMH to south of YNG at 00Z and
will continue to move southeast tonight. Widespread rain is
ongoing across the area with widespread IFR to low IFR
conditions. As the air continues to cool behind the front this
evening we will see rain transition to snow from west to east.
This will coincide with a period of heavier precipitation to
result in a swath of heavy snow extending from FDY-MFD-CLE. The
transition will occur in these areas from 02-03Z before
expanding east towards ERI in the 04-06Z window. Visibilities
will likely drop to a 1/4 to 1/2 mile for a one to three hour
window allowing for quick accumulations before precipitation
ends or weakens. Lake enhanced snowfall will linger in the
snowbelt later tonight and into Sunday. Northwest winds will
also tend to increase this evening as the colder air arrives
with many sites gusting to 20-25 knots. MVFR clouds expected to
linger for much of the day on Sunday.
OUTLOOK...Non-VFR possible into Sunday afternoon in snow
showers, mainly at KCLE, KYNG and KERI.
&&
.MARINE...
Northwest flow will occur over the lake tonight through Sunday in
the cold air advection. Winds 15 to 25 knots will cause small
craft advisory conditions on the lake tonight and Sunday. Winds
will begin to diminish Sunday night into Monday as the flow shifts
around to the southwest by Monday afternoon. Otherwise, generally
light winds expected through the middle part of the week.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Winter Weather Advisory until 10 AM EDT Sunday for OHZ010>013-
020.
PA...None.
MARINE...Small Craft Advisory until 9 PM EDT Sunday for LEZ144>149.
&&
$$
SYNOPSIS...Greenawalt
NEAR TERM...KEC/Greenawalt
SHORT TERM...Lombardy
LONG TERM...Lombardy
AVIATION...KEC
MARINE...Lombardy
Area Forecast Discussion
National Weather Service Jacksonville FL
843 PM EDT Sat Mar 30 2019
.UPDATE...
Sfc ridge is south of the area will continue to push southeast of
the area tonight, as a cold front moves into the FL panhandle,
central GA and SC by Sunday morning. JAX sounding continues to
show dry airmass with PWATs of just under 1 inch, with satellite
imagery showing some deeper moisture over srn FL and along the
approaching cold front from lower MS Valley into central TN.
Radar and satellite show sea breezes have merged inland this
evening but noting only thin line of fair wx clouds. Otherwise,
we are likely to see increasing high clouds tonight into Sunday
morning. Sufficient low level moisture and light boundary layer
winds will allow for some patchy fog. SREF and HRRR still
suggesting this potential, in addition to low stratus, across the
Suwannee Valley area. Little change was made to the fog area in
the grids and min temps in the 50s tonight.
&&
.AVIATION...
VFR looks to prevail through at least late Sunday morning or early
Sunday afternoon, except some chance of fog and/or stratus at
KGNV after 09z until about 13z Sunday morning. With the cold
front moving into the area Sunday midday time frame, have shown
vicinity showers and a chance of t-storms after about 19z, with
the frontal passage across the northeast FL terminals roughly
19z-23z, and a bit sooner at KSSI. Light winds tonight become
southwest and west on Sunday around 10G20kt.
&&
.MARINE...
South-southeast winds near 10 kt this evening will veer to the
south-southwest overnight and increase a bit. Seas 2-4 ft, 3-5 ft
offshore look good. Little change in the current forecast.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 58 76 47 56 / 0 20 10 30
SSI 60 77 50 57 / 0 60 30 60
JAX 58 82 53 60 / 0 90 40 70
SGJ 60 80 56 63 / 0 40 50 80
GNV 57 83 54 62 / 0 30 40 80
OCF 56 83 56 67 / 0 0 30 70
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
Shashy/Sandrik
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1055 PM EDT Sat Mar 30 2019
.UPDATE...
Issued at 1055 PM EDT SAT MAR 30 2019
A cold front continues to move across Eastern KY at this time. The
boundary currently extends from Elliott County near Sandy Hook
south to near Jackson to near Williamsburg. Wind gusts near and
behind the front have been in the 35 to 45 mph range over much of
Central KY into the western part of the CWA. With the potential
for gusts over the next few hours until the front moves east of
the area and the pressure gradient subsides, opted to issue an
SPS. No lightning has been detected in KY for over an hour so
opted to speed up the end of isolated thunder across the region.
Some minor adjustments have been made to pops to account for
recent radar trends with additional adjustments to winds and
hourly temperatures.
UPDATE Issued at 817 PM EDT SAT MAR 30 2019
Hourly pops have been trended toward recent convective allowing
models, especially HRRR and HRRR time lag probabilities and radar
trends. A cold front will move across the region late this
evening into the overnight hours. Gusty winds should continue
throughout the evening and into the overnight hours. A line of
more intense showers and some strong to severe thunderstorms is
ongoing over Central KY and middle TN near the front and this
line should approach the region over the next hour or so and then
progress east across the area. This line likely will weaken with
loss of daytime heating, though trends will be closely monitored.
Gusty winds will be the main concern with these.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 405 PM EDT SAT MAR 30 2019
18z sfc analysis shows the approach of the elongated low/cold
front to our northwest. While we have been in the warm sector of
this system all day, the convection has been mostly limited to
points west and north of the JKL CWA through the afternoon. Gusty
southwest winds of 10 to 20 mph with gusts up to 35 mph have
certainly brought in warm air, as well. Temperatures soared into
the mid to upper 70s across the area thanks to these winds and
the thinning of the cloud cover over much of eastern Kentucky.
Dewpoints stayed generally in the low 50s west to the mid 40s
east, but with rising temperatures the humidity levels did fall
into the 30 to 40 percent range. This has helped to contribute to
a few new wildfires across the area this afternoon in addition to
the ongoing ones in McCreary, Laurel, and Leslie Counties. SPC has
raised the threat for severe thunderstorms later this evening as
the front approaches with the Slight Risk category now touching
the western fringes of the CWA and a much larger Marginal Risk
area. This seems appropriate given the enhanced instability
thanks to our warmer temperatures - though the SPC-HRRR is not
much different from the earlier runs for later this evening across
eastern Kentucky.
The models are in good agreement aloft through the short term
portion of the forecast. They all depict a descended node of the
large North American trough swinging through the Ohio Valley and
across Kentucky tonight. This will bring a healthy slug of mid
level energy across the state initially through around midnight
with a secondary surge passing by midday Sunday. The height falls
move through the JKL CWA early Sunday morning with the whole
system lifting off to the northeast later in the day. Heights will
then rebound tepidly Sunday night and into Monday morning
followed by more zonal 5h flow. Given the good model agreement
will favor a blended solution with a strong nudge toward the CAMs
and in particular the SPC HRRR for PoPs and thunder chances into
the night.
Sensible weather will feature an active evening across the
area with the approach and passage of the cold front. Gusty
southwest winds will diminish after sunset and then switch to the
northwest as the front passes. A solid band of showers will
accompany the front with a broken line of thunderstorms likely as
they enter the CWA - weakening with its eastward progress. There
is a chance for severe storms at the leading edge of these
depending on how they develop over central parts of the state in
the next few hours. Will continue to maintain the heightened
wording in the HWO for this threat. The front then brings in much
colder air after midnight on northwest winds. The air column many
cool off enough for a touch of snow as the pcpn departs into
Sunday morning - but with warm ground temperatures no accumulation
is expected. Chilly conditions will be the rule for Sunday
despite an afternoon return of sunshine for most places. The
clearing skies then set up a very cold night with ridge to valley
differences at play as well. With the start of the growing season
underway will continue the freeze watch for our active counties
into Monday morning.
The CONSShort and ShortBlend guidance where used as the starting
point for the grids with some significant adjustments to low
temperatures Sunday night on account of favorable radiational
cooling conditions for a moderate ridge to valley temperature
split. As for PoPs, the only adjustments were to linger them a
tad longer in the eastern higher terrain through mid morning
Sunday.
.LONG TERM...(Monday through Saturday)
Issued at 245 PM EDT SAT MAR 30 2019
Most of the extended will see warm and dry weather associated with a
large ridge of high pressure, which will be sprawled across the
region from Monday through most of Thursday. Things will start off
cooler than normal, however, as some colder air is expected to still
be in place after a cold front pushes through the area tonight and
Sunday. Monday will be the coolest day next week, with highs only
forecast to make it into the upper 40s and lower 50s that day. After
that, a steady warm up will take place. Highs on Tuesday will still
be a bit below normal, but warmer than Monday, with max values in
the upper 50s to 60 on tap across the area. From Wednesday onward,
we can expect daily highs in the mid to upper 60s for most
locations. A few readings may even reach the lower 70s on Thursday
and Friday. We should see lows in the 30s Monday night and Tuesday
night. Widespread frost will still be in place early Monday morning,
but should melt off my mid morning. Temperatures are then expected
to be much warm from mid week onward, with nightly lows in the 40s
expected for the area. A few spots may only fall to 50 Thursday
night. Our next good chance of rain will be from Thursday afternoon
through Friday night, as a strong area of low pressure moves across
the lower Great Lakes and Ohio Valley regions. A weather system
passing to our south will bring scattered clouds to eastern Kentucky
on Tuesday, but this system should remain far enough south of us to
keep any precipitation out of the area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 815 PM EDT SAT MAR 30 2019
Initially gusty south to southwest winds will be the main
aviation concern to begin the period with gusts up to 25KT. A
cold front will approach the area with showers along and in
advance of it. A gradual decrease into the MVFR range is expected
as showers and some thunderstorms arrive from west to east between
1Z and 5Z. Some brief IFR CIGS and or VIS is possible with the
more intense showers. With this activity have included a few hours
of VCTS and although localized gusts over 30KT are possible,
confidence in that magnitude was too low to include at this time.
Winds will become more west and then northwest rather quickly behind
the front with gusts up to 25KT or so still possible. Winds and
gusts should then gradually diminish between 6z and 12Z. As drier
air moves in from the west, ceilings should improve into the VFR
range between about 12Z and 16Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Freeze Watch from Sunday evening through Monday morning for
KYZ058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...JP