Alert archive / Florida / Special Weather Statements in 2018
Special Weather Statement, NWS Melbourne, FL
NWS Melbourne, FL issued this special weather statement at May 20, 2018, 5:00 AM EDT for Saint Lucie County, Florida. It was in force for 30 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- May 20, 2018, 5:00 AM EDT (09:00 UTC)
- Expired
- May 20, 2018, 5:30 AM EDT
- In force
- 30 min
- Issued by
- NWS Melbourne, FL
County Saint Lucie County, FL
The radar
The Melbourne radar (KMLB), 80 km from the middle of the area, began a volume at 09:01 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Cape Canaveral, FL (KXMR), launched 00:00Z, 9.0 hours before the alert went out and 114 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 23 J/kg
- Mixed-layer CIN
- -56 J/kg
- Mixed-layer LCL
- 959 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 16 m²/s²
- 0-3 km storm-relative helicity
- -39 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
The text
As transmitted.
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</html>What forecasters said that day
The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Melbourne, FL wrote its last area forecast discussion before this special weather statement went out at May 20, 4:58 AM EDT, 2 minutes earlier.
Area forecast discussion, May 20, 4:58 AM EDT, 2 minutes before
Area Forecast Discussion National Weather Service Melbourne FL 458 AM EDT Sun May 20 2018 .DISCUSSION... Current...Increasing south flow in the low to mid levels continues to draw a significant plume of moisture up the peninsula this morning. Numerous showers over the southern peninsula, aided by coastal convergence and favorable lift aloft will spread across the Treasure Coast and as far north as Cape Canaveral early this morning. Potential for heavy rain and even some lightning will exist along the Treasure Coast, with lighter activity across inland areas like Okeechobee and Osceola counties. Today/Tonight...Plenty of ingredients are in place for another wet day, with the greatest chances for precipitation transitioning from the coast this morning to inland areas this afternoon. South to southeast flow continues to draw an abnormally moist airmass overtop the peninsula as we remain sandwiched between a weak trough over the eastern Gulf of Mexico and high pressure over the western Atlantic. Though surface heating will be minimal given the opaque cloud cover, coastal convergence and embedded pieces of energy rounding the mid/upper level trough should spark several rounds of showers with embedded isolated thunderstorms. PoPs were kept high (60-70%) areawide; however, feel that the best rain chances will transition from the nearshore Atlantic waters and adjacent coastal areas this morning to inland areas this afternoon as some dry air advects in from the southeast. Repeated bouts of heavy rainfall with accompanying localized flooding pose the greatest weather threat today, though storms will also be capable of producing wind gusts between 30 to 40 mph and lightning. Max temperatures forecast within a degree or two of 80 (below normal for mid May) to account for expected cloudy skies and rain. There is some uncertainty with respect to how much drying will advect in from the southeast later today. Regardless, most models indicate a renewed push of deep moisture advecting northward overnight. This should transition the highest chances for precipitation back to the coast, especially south of Cape Canaveral. Overnight mins a couple of degrees above climo, particularly along the coast given the mild onshore flow. Mon-Sat...The Atlantic ridge axis will remain the dominant weather feature with a moist south to southeast flow keeping rain chances above normal (50 to 60 percent) most days supporting mainly daytime showers and storms. The ridge axis is forecast to gradually shift southward and weaken during mid to late week as a trough develops over the Southeast US. A slight reduction in the deep moisture by Wed will allow rain chances to decrease to 30-40 percent for most areas. It will remain humid with max temps in the mid 80s. Both GFS and ECMWF show a mid level trough developing over the Gulf of Mexico late in the week. The GFS retrogrades a piece of energy SW from the base of a departing shortwave trough off the US east coast. The real difference is how each model handles lower pressure at the surface. The ECMWF continues to show low pressure developing directly underneath the upper low over the central Gulf on Fri. This looks suspect as the best support for sfc low pressure would be to the ascending (east) side of the upper low, closer to the GFS solution. But both models show deep tropical moisture overspreading the FL peninsula during the first part of the upcoming holiday weekend which will prompt high rain chances with a threat for heavy rain and localized flooding due to already wet conditions. && .AVIATION...Highest rain chances along coastal terminals through early afternoon before activity develops and spreads inland this afternoon. Widespread MVFR VSBYs likely in rain with spotty IFR tough to time. Ceilings VFR to occasional MVFR in showers and isolated storms. && .MARINE... Today/Tonight...Synoptic pattern supports 10-15 knots of east to southeast flow this morning, however, widespread showers and isolated thunderstorms are disturbing the wind flow. Expect generally southeast winds to develop this afternoon as best chance for showers transitions inland. Winds 10-15 knots nearshore and 15- 20 knots nearshore will keep seas choppy: 3-4 near the coast, up to 6 feet well offshore. Monday-Thursday...The axis of the Atlantic high pressure ridge will stay north of the waters into Wed. The models show this will continue to produce a breezy southeast wind flow and rather agitated seas at least through Tue. By Thu, the ridge axis is forecast to settle into the waters, which should knock winds down closer to 10 knots. Moisture is forecast to decrease a bit during mid week, as early as Tue, so periods of showers with isolated storms should become less frequent. && .PRELIMINARY POINT TEMPS/POPS... DAB 80 73 82 69 / 70 40 60 30 MCO 79 71 84 71 / 70 40 60 20 MLB 81 74 83 72 / 70 40 60 30 VRB 81 73 83 71 / 70 50 60 30 LEE 80 71 84 70 / 70 50 60 20 SFB 79 71 84 69 / 70 40 60 20 ORL 79 71 84 70 / 70 40 60 20 FPR 81 73 83 71 / 70 50 60 30 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && SHORT TERM...Ulrich LONG TERM....Kelly AVIATION...Ulrich
Hazardous weather outlook, May 19, 9:32 PM EDT, 7 hours 28 minutes before
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</html>In the hours before
Special weather statement, May 20, 5:00 AM EDT, 0 minutes before
Special Weather Statement
National Weather Service Melbourne FL
500 AM EDT SUN MAY 20 2018
FLZ059-200930-
St. Lucie-
500 AM EDT SUN MAY 20 2018
...A STORM WITH THE POTENTIAL OF DEVELOPING FUNNEL CLOUDS WILL AFFECT
NORTHEASTERN ST. LUCIE COUNTY...
At 459 AM EDT, a strong thunderstorm was located over Fort Pierce,
moving northwest at 10 mph.
Locations impacted include...
Fort Pierce, Indrio, White City, Fort Pierce Inlet and Lakewood Park.
Torrential rainfall is also occurring with this storm and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.
Funnel clouds can occasionally touch down and produce brief small
tornadoes. Move indoors and stay away from windows.
LAT...LON 2743 8028 2743 8030 2744 8030 2745 8032
2742 8031 2742 8030 2740 8030 2736 8033
2752 8054 2756 8040 2756 8036 2750 8034
2747 8029 2746 8032 2744 8028
TIME...MOT...LOC 0859Z 138DEG 10KT 2744 8035
KellyThe office that day
Everything else NWS Melbourne, FL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 20, 3:27 AM EDT | Special Marine Warning | MLB | 63 min | |
| May 20, 5:51 AM EDT | Areal Flood Advisory | MLB | Martin, Saint Lucie | 84 min |
| May 20, 6:35 AM EDT | Areal Flood Advisory | MLB | Indian River | 85 min |
| May 20, 7:58 AM EDT | Special Weather Statement | MLB | Osceola | 47 min |
| May 20, 9:14 AM EDT | Areal Flood Advisory | MLB | Indian River, Martin, Saint Lucie | 2 hr |
Nearby
Special Weather Statements in Florida, 2018Every special weather statement in 2018
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.