ATL: INVEST 90L - Models

[Bocadude85]

The 12Z ECMWF actually shows a strong depression, not a TS, hitting St. Petersburg/Tampa in five days. The maximum 850-mb wind on the charts is 19 m/s, which converts to about 29 kt (34 mph) at the standard 10-m elevation. So the landfall intensity shown is about 30 kt/1003 mb. South FL would actually want to see a slightly stronger storm to maximize upward convergence and rainfall totals. We all could use the rain for the entire state as our rainy season has been slow to begin!

The rainy season has been going strong down here in South Florida, we definitely do not need anymore rain.

[blp]

The 12Z ECMWF actually shows a strong depression, not a TS, hitting St. Petersburg/Tampa in five days. The maximum 850-mb wind on the charts is 19 m/s, which converts to about 29 kt (34 mph) at the standard 10-m elevation. So the landfall intensity shown is about 30 kt/1003 mb. South FL would actually want to see a slightly stronger storm to maximize upward convergence and rainfall totals. We all could use the rain for the entire state as our rainy season has been slow to begin!

The rainy season has been going strong down here in South Florida, we definitely do not need anymore rain.

I second that. We are above normal down here.

[supercane4867]

TD in 72hrs

[IvanSurvivor21]

Could anyone post links to the latest model loops (Euro, GFS, CMC)? If possible? Thanks.

[bamajammer4eva]

Tonights model runs show...



OOPS Forgot to add what the Canadian does later @ 132h fwiw

[jlauderdal]

The 12Z ECMWF actually shows a strong depression, not a TS, hitting St. Petersburg/Tampa in five days. The maximum 850-mb wind on the charts is 19 m/s, which converts to about 29 kt (34 mph) at the standard 10-m elevation. So the landfall intensity shown is about 30 kt/1003 mb. South FL would actually want to see a slightly stronger storm to maximize upward convergence and rainfall totals. We all could use the rain for the entire state as our rainy season has been slow to begin!

euro looking real wet for next week, slow start to the rainy season, really?

[MiamiensisWx]

The 12Z ECMWF actually shows a strong depression, not a TS, hitting St. Petersburg/Tampa in five days. The maximum 850-mb wind on the charts is 19 m/s, which converts to about 29 kt (34 mph) at the standard 10-m elevation. So the landfall intensity shown is about 30 kt/1003 mb. South FL would actually want to see a slightly stronger storm to maximize upward convergence and rainfall totals. We all could use the rain for the entire state as our rainy season has been slow to begin!

The rainy season has been going strong down here in South Florida, we definitely do not need anymore rain.

? I have not seen a statement by the NWS Miami office that the rainy season has "officially" begun. A few weeks of rain do not make a rainy season: the NWS uses different criteria to determine when it begins.

http://www.srh.noaa.gov/mfl/?n=summer_season

For the more recent 33 years (1965-1997) when all three parameters were available, they were used in the following manner to determine the beginning of the summer [i.e. rainy] season. The average daily dew point temperature was first examined to determine when it rose above and remained above 70oF. Of course, from this time on, the daily minimum temperatures remained above the 70oF level. The date when this took place was designated as the beginning of the summer season. In nearly all years, the summer rains began on or soon after that date.

[HURAKAN]

? I have not seen a statement by the NWS Miami office that the rainy season has "officially" begun. A few weeks of rain do not make a rainy season: the NWS uses different criteria to determine when it begins.

"This will probably come as no big surprise, but we have determined that the rainy season has started effective Saturday, May 18th. The start date of the rainy season is typically determined "after-the-fact" once it is clear that the typical South Florida rainy season pattern of showers and thunderstorms has become established and no prolonged dry periods are anticipated. "

[SouthDadeFish]

The 06Z GFS provided a very messy solution. It seems the disturbance in the BoC was not the main trigger for genesis, but rather it was the area of convection in the NW Caribbean. Then it slides NE while in the Gulf and ultimately gets sheared apart. Then another low forms east of Florida. It appears even if anything does form, the main threat to the Florida area will be the same: very heavy rainfall over the next week.

[jlauderdal]

Miami nws and others were not liking the gfs at all, they threw it out...see the disco from miami nws

[jlauderdal]

Miami nws and others were not liking the gfs at all, they threw it out...see the disco from miami nws

[MiamiensisWx]

Miami nws and others were not liking the gfs at all, they threw it out...see the disco from miami nws

NWS Miami is probably only alluding to the 00Z GFS, which shows more development than either the 06Z GFS or the 00Z ECMWF.

ATTENTION THEN TURNS TO THE GULF OF MEXICO AS A MONSOON TROUGH/LOW
PUSHES NORTHEASTWARD OUT OF THE BAY OF CAMPECHE AND ACROSS THE
YUCATAN PENINSULA. THE GFS DEVELOPS THE LOW AND MOVES IT ACROSS
SOUTH/CENTRAL FLORIDA ON WEDNESDAY. THE MODEL IS SUFFERING FROM
CONVECTIVE FEEDBACK TIED TO MID LEVEL VORT ENERGY AND STRENGTHENS
THE LOW AND THEN THE SURROUNDING FLOW TOO MUCH AND TOO FAST. SO IT
HAS BEEN DISCARDED. THE 12Z/00Z ECMWF KEEPS THE SURFACE AREA OF
LOW PRESSURE NEAR THE YUCATAN ON TUESDAY...GETTING PICKED UP INTO
THE GULF AS AN UPPER LEVEL TROUGH MOVES ACROSS THE SOUTHEAST.
THE LOW/MID LEVEL PRESSURE GRADIENT BEGINS TO TIGHTEN WITH DEEPER
MOISTURE MOVING FURTHER NORTH. AN UPPER LEVEL TROUGH IS EXPECTED
TO MOVE ACROSS THE SOUTHEAST...WITH UPPER LEVEL ENERGY MOVING
ACROSS THE BASE OF THE TROUGH INTO SOUTHWEST FLORIDA. THE 850MB
FLOW IS EXPECTED TO STRENGTHEN TO AROUND 30 KNOTS MONDAY NIGHT
OVER THE GULF WATERS AND TOWARDS NAPLES...AND 0-1KM HELICITY
VALUES ARE ALSO EXPECTED TO INCREASE. SO THERE IS THE SOME
POTENTIAL FOR STRONGER STORMS OVER THE GULF AND TOWARDS THE NAPLES
REGION. THE HEAVY RAINFALL THREAT MAY ALSO BEGIN MONDAY NIGHT FOR
THE GULF COAST AND THEN INTO ALL OF SOUTH FLORIDA ON TUESDAY OR
WEDNESDAY AS UPPER LEVEL DIVERGENCE INCREASES AND PRECIPITABLE
WATER VALUES INCREASE POSSIBLY TO AROUND 2.5 INCHES.

THE 00Z ECMWF RUN BACKS OFF ON DEVELOPMENT OF A LOW IN THE GULF.
HOWEVER...THE TIMING IS LARGELY UNCHANGED...AND THIS BRINGS SOME
CONSISTENCY TO THE FORECAST. THERE IS STILL A LOT OF UNCERTAINTY
WITH THE DEVELOPMENT AND TIMING OF THE SYSTEM AND WHEN THE HEAVY
RAIN THREAT WILL BEGIN AND THEN FINALLY END. HOWEVER...IT APPEARS
THAT THE HEAVY RAINFALL THREAT COULD BEGIN AS EARLY AS
MONDAY...AND BASED ON THE ECMWF...COULD CONCEIVABLY CONTINUE
THROUGH THE ENTIRE WEEK. THERE IS ALSO A THREAT OF MINI
SUPERCELLS SOMETIME POSSIBLY IN THE MID WEEK PERIOD...ESPECIALLY
IF THE SYSTEM DOES DEVELOP SOMEWHAT IN THE EASTERN GULF. THE 12Z
ECMWF HAD THE 850MB FLOW STRENGTHENING TO AROUND 40 KNOTS IN THE
MID WEEK PERIOD...WITH 0-1KM HELICITY VALUES ALSO INCREASING.
HOWEVER...THE 00Z RUN HAS BACKED OFF ON THIS SLIGHTLY. IT IS STILL
WAY TOO EARLY TO PICK OUT ANY TIMING OF A MINI SUPERCELL THREAT
OR IF IT WILL EVEN OCCUR...BUT THERE IS SOME POSSIBILITY SO THAT
IS WHY IT IS MENTIONED. THE WEATHER PREDICTION CENTER PAINTS THE
REGION WITH AREAWIDE TOTALS OF 7-10 INCHES OVER THE NEXT 7 DAYS.
THIS IS VERY CLOSE TO WHAT THE ECMWF OUTPUTS ACROSS THE REGION AS
WELL. WITH THE GREATER RUN TO RUN CONSISTENCY FROM THE
ECMWF...THIS COULD VERY WELL OCCUR. HOWEVER...WITH VARYING
SOLUTIONS FROM THE MODELS...THE CONFIDENCE IN THE TOTAL AMOUNT OF
RAINFALL IS STILL RELATIVELY LOW. A HYDROLOGIC OUTLOOK WILL BE
ISSUED LATER THIS MORNING TO HIGHLIGHT THIS HEAVY RAIN POTENTIAL
AS WELL.

http://forecast.weather.gov/product.php?site=MFL&issuedby=MFL&product=AFD&format=CI&version=2&glossary=1

[MiamiensisWx]

? I have not seen a statement by the NWS Miami office that the rainy season has "officially" begun. A few weeks of rain do not make a rainy season: the NWS uses different criteria to determine when it begins.

"This will probably come as no big surprise, but we have determined that the rainy season has started effective Saturday, May 18th. The start date of the rainy season is typically determined "after-the-fact" once it is clear that the typical South Florida rainy season pattern of showers and thunderstorms has become established and no prolonged dry periods are anticipated. "

Ah, I missed that quote. Thanks!

[SouthDadeFish]

When they wrote that discussion the 06Z GFS wasn't available yet and you did not put the part where they specifically said:

"THE 00Z GFS IS SUFFERING FROM CONVECTIVE
FEEDBACK ISSUES...SO CONSENSUS AMONG THE SURROUNDING OFFICES WAS
TO USE THE 12Z ECMWF FOR THE FORECAST PAST THIS WEEKEND."

[MiamiensisWx]

When they wrote that discussion the 06Z GFS wasn't available yet.

Oh, thanks for the correction. If you look at the 00Z and 06Z GFS runs, the upper-level shear vectors appear to be parallel to the 850-mb flow. Would that not mean lower effective shear if a weak low were to move NE across S FL as the GFS and ECMWF suggest? I made a post on this in the other thread, which is linked below. Also, the 12Z run may show less shear, as yesterday's 12Z run did here.

http://www.storm2k.org/phpbb2/viewtopic.php?p=2308892#p2308892

[weatherwindow]

According to nws/mia and HPC, SFla is under a zone of deformation which apparently will enhance rainfall during next week in concert with the disturbance out of the GOM...can someone explain the term: zone of deformation..Thanks, Rich

http://forecast.weather.gov/product.php ... glossary=1

[MiamiensisWx]

According to nws/mia and HPC, SFla is under a zone of deformation which apparently will enhance rainfall during next week in concert with the disturbance out of the GOM...can someone explain the term: zone of deformation..Thanks, Rich

http://forecast.weather.gov/product.php ... glossary=1

Deformation Zone
The change in shape of a fluid mass by variations in wind, specifically by stretching and/or shearing. Deformation is a primary factor in frontogenesis (evolution of fronts) and frontolysis (decay of fronts).

Basically, this enhances upward motion across S FL, meaning increased moisture convergence and precipitation if the thermodynamics are ripe.
http://w1.weather.gov/glossary/index.php?letter=d

Google is your friend.

[SouthDadeFish]

Yes I saw your post on the other thread and you have the right train of thought. By the way I think you meant "right-entrance" region instead of right-exit. That is the part that provides large scale ascent. However, 200mb winds although in the same direction, may simply be too strong. You can still have speed shear. I see 200mb winds of 45-60 knots in the eastern Gulf in 48-72 hours. So even if you have 20 knots of wind at 850mb in the same direction then shear is still 25-40 knots. It may be too much to allow a surface circulation to develop. However, there will probably be a large area of upper-level divergence which will promote rising motion and convection. Notice how the 00Z Euro didn't really develop a consolidated low, but instead strung out 850mb vorticity in a elongated SW-NE area. I'm growing skeptical of anything developing, and if it does, it will most likely be the typical June sheared mess.

[OuterBanker]

Looks like the Arc business will be booming in Florida this week. Geeze, GFS has a foot of water in areas of FL this week. Also looks like most models have shifted to the through FL and up coast scenario too (I see that the Canadian is on steroids again, thought they fixed that). Too early for any real development, I don't think it will get a name. But, it will be a real soaker. If this was early July it would be a different story. And as most know here. Early season storms have little bearing on the rest of the season.

[SouthDadeFish]

DEFORMATION ZONE (DFRMTN ZN) - An area in the atmosphere where winds converge along one axis and diverge along another. Deformation zones (or axis of deformation as they are sometimes referred to) can produce clouds and precipitation.

http://www.theweatherprediction.com/jargon/