Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/02/20
Area Forecast Discussion
National Weather Service Honolulu HI
352 PM HST Fri May 1 2020
.SYNOPSIS...
Strong high pressure north of the state will maintain gusty trade
winds through the weekend. A stable atmosphere will relegate
showers to mainly windward and mountain areas. A decaying cold
front may weaken trade winds next week and increase shower
coverage.
&&
.DISCUSSION...
Strong high pressure north of the state is maintaining gusty
trade winds across the islands. The wind advisory that had been
effect for portions of Maui County and the Kohala Mountains on the
Big Island had been cancelled. Winds have dropped below the advisory
threshold in those areas but remain gusty. Through the weekend,
low clouds riding the trades will bring passing clouds and showers
to mainly windward and mountain areas with a few quick showers
reaching leeward areas of the smaller islands. The leeward Big
Island will see increasing clouds in the afternoons with some
embedded showers, and clearing skies at night.
The current atmosphere is extremely stable with ridging aloft
creating a strong temperature inversion near 6000 feet, as shown
by both soundings from Hilo and Lihue. The upper ridge will
maintain the stable atmosphere through Monday, relegating most of
the showers to windward and mountain areas. Next week, a decaying
surface front accompanied by an upper trough may increase island
shower coverage and intensity by Wednesday, and decrease trade
wind speeds.
&&
.AVIATION...
Surface high pressure north of the state will allow for moderate
to occasionally strong east northeasterly trades continue this
afternoon. This may create tempo moderate turbulence for aircraft
on the leeward side of the mountains. Isolated showers will
mainly affect windward portions of the islands over the next
several hours. By tonight, expect an increase in cloud coverage
and showers along the windward slopes and coasts with accompanying
brief MVFR conditions.
AIRMET SIERRA remains in effect for north thru east sections of
Maui for tempo mountain obscuration above 2500 feet due to clouds
and showers.
AIRMET TANGO remains in effect for south thru west of mountains on
all islands below 8000 feet due to moderate turbulence.
&&
.MARINE...
High pressure north and northwest of the state will help maintain
fresh to strong trade winds through Monday. The trades will ease
Tuesday and Wednesday next week as a trough sets up just north of
the island chain. A Small Craft Advisory (SCA) remains in effect
for most marine zones through Sunday due to the trade wind
speeds. The SCA may need to be extended further for some coastal
waters beyond Sunday.
A series of north to northwest swells will move through the
islands during the next week, keeping steady small to moderate
sized surf in place along north and west facing shores. Surf along
east facing shores will hold steady through the weekend, then
lower a bit heading into the middle of next week as the trades
ease. Small background southerly swells will continue along south
facing shores through the middle of next week. Surf is expected to
remain below advisory thresholds along all shores through the
middle of next week.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Sunday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui
County Windward Waters-Maui County Leeward Waters-Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.
&&
$$
DISCUSSION...Morrison
AVIATION...Thomas
MARINE...Foster
Area Forecast Discussion
National Weather Service Great Falls MT
855 PM MDT Fri May 1 2020
.UPDATE...
For the most part, inherited forecast is tracking well. Saturday
at 18Z, increased POPs slightly along our border to come in line
with surrounding offices. Then increased POPs across Southwest
Montana to allow a minimal increase in moisture, especially in the
mountains, about 3 hours earlier than the previous shift
forecast. After that, interpolated the next two hours up to 21Z,
allowing for a smooth transition to a chance of moisture in some
areas of the Southwest, and one that lines up nicely with the
forecasts of our bordering Weather Forecast Offices. Tweaked Sky
conditions just a bit, and reran QPF, etc.. Additionally,
increased our chance of thunderstorm, slightly during the time
period, Saturday 18Z to 00Z Sunday, keeping chance of thunderstorm
at slight chance or less, but still better conveying current
analysis and model guidance, while aligning well with our Forecast
Office Neighbors. No changes to temperatures, humidity or winds,
at this time.
- Fogleman
&&
.SYNOPSIS...
A few light rain showers will affect North Central MT early this
evening, otherwise expect quiet weather conditions through early
Saturday afternoon. Then another round of showers and stronger
winds will move through the region from Saturday evening through
Sunday. Temperatures will cool a bit early next week, with more
showers or thunderstorms possible by late next week.
&&
.AVIATION...
Updated 603 PM MDT Fri May 1 2020 (02/00Z TAF Period)
Expect VFR conditions throughout this TAF period at all airfields
with one exception. After 03/00Z KBZN is forecast to become MVFR,
4SM -SHRA BR, intermittently. Additionally, expect mountain
obscurations along The Divide and in Southwest Montana beginning
around 03/00Z. At the onset of this TAF period, gusty winds up to
24KT are forecast for KCTB, KHLN and KGTF, with periods of winds
gusting to 18KTS at KEKS. These winds will impact light aircraft
mostly near mountains and in passes.
For details on ICG, TURBC and more, please see:
aviationweather.gov/icing
aviationweather.gov/turbulence
- Fogleman
NOTE: Amendments not scheduled for Ennis (KEKS) due to ongoing
runway closure.
&&
.PREV DISCUSSION...
/ISSUED 603 PM MDT Fri May 1 2020/
Tonight through Sunday...With some cold air aloft over North
Central MT this afternoon, the airmass has become a touch
unstable, allowing for a few light rain showers to develop over
North Central MT. Most of these showers should diminish by 7 PM,
and any precipitation amounts this evening will be light. It is a
quiet start to the day on Saturday, but the next upper level
disturbance arrives over the western portions of the region by
late Saturday afternoon. A few showers/isolated thunderstorms will
accompany this disturbance. The precipitation continues into
Sunday, as a cold front moves through the region. Surface winds
will also increase, especially along the front range of the
Rockies and around Cut Bank, but overall wind speeds should remain
just below warning criteria as of now.
Monday through Friday...Several weather disturbances will try to
move through the region during the middle to later portions of
next week. Overall confidence in timing/strength of each system is
still a bit uncertain, as each model has a slightly different
solution. Thus, the overall blend of the NBM model seems to have a
good handle on temperatures/pops in much of the extended, with
little changes made. Brusda
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 34 70 43 60 / 0 10 20 30
CTB 33 67 42 55 / 0 10 20 20
HLN 37 70 42 60 / 0 20 20 40
BZN 35 69 40 61 / 0 20 30 70
WYS 26 60 30 54 / 10 20 30 70
DLN 35 67 40 57 / 0 20 20 60
HVR 39 70 44 66 / 0 0 20 40
LWT 35 65 42 60 / 0 10 20 60
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
http://www.weather.gov/greatfalls