Sunday, March18, 2018

Marine Weather and Tides
Shepherdsville, KY

Version 3.4
What's New / NOTES
3/3/2018 - There is a new GOES Satellite for the east coast that required rewriting that part of the code. Please report any issues.
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.

Sunrise 7:46AMSunset 7:54PM Sunday March 18, 2018 12:20 AM EDT (04:20 UTC) Moonrise 7:42AMMoonset 8:11PM Illumination 2% Phase: Waxing Crescent; Moon at 1 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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7 Day Forecast for Marine Location Near Shepherdsville, KY
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location: 38, -85.7     debug

Area Discussion for - Louisville, KY
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Fxus63 klmk 172334
area forecast discussion
national weather service louisville ky
734 pm edt Sat mar 17 2018

Updated aviation discussion...

Mesoscale update
Issued at 720 pm edt Sat mar 17 2018
storms have pushed into eastern kentucky and the air mass over
central kentucky has stabilized, so our portion of severe t-storm
watch 10 has been cancelled. There were a few reports of small hail,
but nothing severe that we are aware of.

The remainder of the night should be dry as we are into northerly
low-level flow and cold advection. Last set of updates was issued a
few min ago.

Issued at 550 pm edt Sat mar 17 2018
convection is already on a downward trend after getting a few sub-
severe reports from marion county eastward to lincoln. The main
boundary of concern runs from near greensburg to stanford, and that
will be the main focus of any remaining svr threat. Will start
peeling off the western northwestern layer of counties from WW 10
this hour, with the rest of central ky likely to come down next

Issued at 433 pm est Sat mar 17 2018
storms have developed along a well defined surface boundary
stretching across central ky in an environment characterized by 1000-
1500 j kg surface based instability coincident with 50-55 knots of
effective bulk shear. Given strong speed shear with height along
with some veering with height, supercell structures (some splitting)
are possible. The main concern is large hail given freezing levels
around 8k feet and -20c heights around 18 k feet. A damaging wind
threat will also exist given steep low level lapse rates with a 20
degree t TD spread at the surface. There is a possibility that
storms could congeal, and if a cold pool is established the wind
threat would increase.

An isolated tornado can't be ruled out, however low level surface
winds aren't overly backed to promote horizontal streamwise
vorticity ingestion. In addition, lcl's are in the 1000-1200 m
range. Latest mesoanalysis shows effective SRH values around 50-100
m2 s2 along the boundary so there is some localized enhancement of
the environment along the front.

Severe thunderstorm watch #10 was just issued and expires at
midnight edt. However, expect storms to move east of our area by
around 6-7 pm edt.

Short term (this evening through Sunday night)
issued at 215 pm edt Sat mar 17 2018
as of 2 pm, a surface analysis showed an area of low pressure
centered near owensboro, kentucky. Goes-east mesoscale visible
imagery depicted an arch of enhanced cumulus denoting the warm front
location that was along an owensboro-elizabethtown-lexington line.

South of that boundary, spring-like weather prevailed with mostly
sunny skies, breezy southwest winds, and temperatures in the 70s.

Northward, across southern indiana, lower clouds and easterly flow
prevailed and readings were in the 40s. Across the forecast area,
there is about a 30-35 degree temperature gradient.

A pool of near-60 degree dewpoints lie across south-central
kentucky, contributing to about 500 to 1000 j kg of surface-based
cape, per recent rap mesoanalysis and goes-east CAPE derived
product. Aloft, the presence of a passing shortwave is providing
modest deep-layer shear, on the order of 40 to 50 kts.

In the next 3-5 hours, a brief window of opportunity exists for
strong to marginally severe thunderstorms where the axis of
instability remains as the surface low tracks east through central
kentucky providing the necessary lift to initiate convection. The
available hi-res models show the area where the risk exists is from
around lexington southward toward lake cumberland, and as far west
as glasgow, campbellsville, and springfield kentucky. The latest spc
day 1 outlook nudged the marginal slight risks westward from the
early morning issuance.

The main hazards for any storm that does develop is large hail
(quarter sized) thanks to the lower freezing levels (8-10 kft),
steep low-level lapse rates, and drier air aloft. If storms
organized into small clusters, a damaging wind threat also exists.

The main time frame is from around 3-4 pm through 7 pm as the storms
develop and quickly move eastward into eastern ky tn.

The surface low moves east of the area this evening and drags the
cold front back through the area. There is a drizzle light shower
chance across the northern areas and northern bluegrass later this
evening, then temperatures tonight will fall into the upper 30s to
lower 40s with mostly cloudy to overcast skies.

On Sunday, seasonable readings are expected as high pressure builds
into the region. Drier air working in from north will erode the
cloud layer initially over southern indiana and north central
kentucky, where a mostly to partly sunny day is expected. Further to
the southwest, across south-central and west-central kentucky, the
effects of that dry air are limited and time-height cross sections
show more moisture lingering, so a mostly cloudy to overcast day is
forecast. The clouds will impact high temperatures, and southern
indiana may end up slightly warmer than south-central kentucky by a
few degrees. Most areas will range from 55 to 60.

The next weather system is quick to move into the region as the
upper level pattern remains quite progressive. Showers are likely
Sunday night, especially after midnight across south central and
central kentucky. Lows will fall into the 40s.

Long term (Monday through Saturday)
issued at 220 pm edt Sat mar 17 2018
an unsettled weather pattern is in store for the upcoming work week
across the lower ohio and tennessee valleys. The progressive but
active pattern could bring both spring and winter weather to the

The 17.12z models are in reasonable agreement showing a compact
shortwave tracking across the tennessee valley Monday. At the
surface, a low pressure looks to organize and track across middle tn
during the afternoon and evening hours. This setup will put a warm
front somewhere along the ky tn border or into south-central ky. The
best dewpoint surge, instability, and potential severe weather
threat continues to be across tn al ga. However, a time-trend
analysis over the last several model runs shows a slight northward
jog in the surface low and shortwave, and if this trend continues,
portions of south-central ky could be under a threat for stronger to
severe storms Monday afternoon evening.

Further north, a frontogenetical band of rain is likely to setup
across southern indiana and north central kentucky. As temperatures
cool behind the front Monday night and Tuesday morning, a brief
changeover to wet snow is possible but at this time, the colder air
lags the precipitation enough to preclude much if any snowfall

The Tuesday-Wednesday period has more uncertainty and lower
confidence. The potential phasing or not of the upper level energy
and the southern stream system could spread light precipitation
across portions of eastern and central kentucky. It does appear to
be much colder with highs in the 40s, and potentially staying stuck
in the 30s. For now, continued with a model consensus but will need
to watch this period for the potential for light snow accumulations
across the bluegrass.

The remainder of the work week looks more benign with high pressure
and seasonably cool temperatures. Toward next weekend it appears
another system may track through the midwest and oh valleys and
bring chances for showers and thunderstorms to the area.

Aviation (00z TAF issuance)
issued at 733 pm edt Sat mar 17 2018
scattered storms have now pushed east of the region, with the
frontal boundary that they initiated on also sinking south of the
taf sites. Therefore, we'll stay dry the rest of this forecast
cycle, with steady NW winds slackening and becoming light and
variable later tonight. The biggest concern will be low ceilings
already working into the region from the north, and expected to
persist for much of the overnight. Have the tafs mostly going into
the low MVFR range below fuel-alternate, but can't rule out some
brief ifr at hnb or lex around midnight into the pre-dawn hours.

Covered this potential with a tempo. Ceilings should improve close
to sunrise at sdf lex hnb, but expect them to persist at bwg well
into the afternoon on Sunday.

Lmk watches warnings advisories
In... None.

Ky... None.

Mesoscale... Bjs ras
short term... Zt
long term... Zt
aviation... Bjs

Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Louisville, Standiford Field, KY13 mi25 minNNW 109.00 miOvercast44°F39°F85%1014.8 hPa
Louisville, Bowman Field Airport, KY16 mi28 minNNW 58.00 miOvercast44°F41°F89%1014.8 hPa
Fort Knox, KY16 mi85 minWNW 810.00 miOvercast47°F42°F84%1013.8 hPa

Wind History from SDF (wind in knots)
Last 24hrE6SE3E5N3N8NE4CalmCalmSE3Calm3N8CalmNW4N5N10NW14NW16
1 day agoN5N5N10N8N7N6NE8NE8NE9E8NE8E9NE6NE9E8SE6SE7SE11E8E7E8E6E8E6
2 days agoS6SW8

Tide / Current Tables for
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Weather Map and Satellite Images
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NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Wind Forecast for Louisville, KY (0,6,7,8)
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Ground Weather Radar Station Louisville, KY
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The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerious of sources and is presented automatically. It is not checked for accuracy either by anyone at or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.