Dr. Jeff Masters' WunderBlog

The main severe weather threats for Southern and Central Florida will be possible localized flooding, small hail, and dangerous lightning. I don't see these storms producing very strong winds or even tornadoes, although it can't be ruled out.

its building nicly cchs as for any severe maybe a couple of more hrs

Thanks,.. all radars are useful tools.

Possibly in the areas south and east of the solid area of rain that is moving E from Tampa. The sun has been out and it looks very unstable here.

I do agree with CC that the severe threat is more like our typical summer severe threat. Still there is a warm front moving northward and that will produce some turning of winds at different heights. I still think that heavy rain and lightning are the biggest concern.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MELBOURNE FL
1005 AM EDT SAT MAR 22 2008


...THUNDERSTORM IMPACT...
A WEAK AREA OF LOW PRESSURE OVER THE SOUTHEAST GULF OF MEXICO
WILL MOVE EAST ACROSS SOUTH FLORIDA THIS AFTERNOON AND EVENING.
INCREASING COVERAGE OF SHOWERS WILL OVERSPREAD CENTRAL FLORIDA
DURING THE DAY. HEAVIER SHOWERS AND EMBEDDED THUNDERSTORMS ARE
FORECAST TO DEVELOP SOUTH OF ORLANDO...PRIMARILY OVER MARTIN...
SAINT LUCIE AND OKEECHOBEE COUNTIES LATER THIS AFTERNOON INTO
EARLY THIS EVENING. LACK OF INSTABILITY WILL LIMIT THE SEVERE
THREAT. HOWEVER...A RAPID INFLUX OF DEEP MOISTURE AND INCREASINGLY
FAVORABLE SPEED AND DIRECTIONAL SHEAR IN ASSOCIATION WITH A WARM
FRONTAL BOUNDARY LIFTING NORTH...MAY ALLOW FOR ONE OR TWO
ORGANIZED AND PERSISTENT STORMS TO DEVELOP AND PRODUCE LARGE
HAIL...DAMAGING WINDS AND EVEN A TORNADO...FROM LAKE OKEECHOBEE TO
THE TREASURE COAST. THIS SYSTEM IS EXPECTED TO CONTINUE MOVING
EAST ACROSS THE NORTHERN BAHAMAS AND AWAY FROM THE AREA OVERNIGHT.

...FLOOD IMPACT...
HEAVY DOWNPOURS MAY LEAD TO TEMPORARY FLOODING OF STREETS AND
OTHER LOW LYING OR POORLY DRAINED AREAS...MAINLY ACROSS MARTIN...
SAINT LUCIE AND OKEECHOBEE COUNTIES THIS AFTERNOON INTO EARLY
EVENING. TOTAL RAINFALL ACCUMULATIONS SHOULD APPROACH ONE INCH IN
THIS AREA WITH LOCALLY HIGHER AMOUNTS NEAR 2 INCHES POSSIBLE.
SIGNIFICANTLY LESS RAINFALL AMOUNTS TO THE NORTH.

...RIP CURRENT IMPACT...
...HIGH RISK OF RIP CURRENTS TODAY...
LONG PERIOD OCEAN SWELLS WILL CONTINUE TO PROPAGATE INTO THE SURF
ZONE AT EAST CENTRAL FLORIDA BEACHES...RESULTING IN A HIGH RISK
OF STRONG RIP CURRENTS TODAY. BEACH GOERS ARE URGED TO CHECK WITH
BEACH PATROL FOR LOCAL CONDITIONS BEFORE VENTURING INTO THE WATER.
SWIM WITHIN SIGHT OF A LIFEGUARD AND NEVER SWIM ALONE. EVEN THOSE
USING SURF OR BOOGIE BOARDS SHOULD USE CAUTION.

...MARINE THUNDERSTORM GUST IMPACT...
WIDESPREAD SHOWERS WITH EMBEDDED THUNDERSTORMS WILL MOVE OFFSHORE
THE TREASURE COAST AND ACROSS THE INTRACOASTAL AND ADJACENT
ATLANTIC WATERS THIS AFTERNOON AND EVENING. THE PRIMARY THREAT
WILL BE OCCASIONAL CLOUD TO GROUND LIGHTNING. A FEW STRONG STORMS
WILL BE CAPABLE OF PRODUCING WIND GUSTS IN EXCESS OF 35 KNOTS.

...WATERSPOUT IMPACT...
THERE IS A VERY LOW THREAT FOR ISOLATED WATERSPOUTS OVER THE
ATLANTIC LATE THIS AFTERNOON AND EVENING...ESPECIALLY IN STORMS
THAT MOVE OFFSHORE THE TREASURE COAST.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.
HAZARDOUS BOATING CONDITIONS ARE EXPECTED TO DEVELOP ON MONDAY AND
CONTINUE TUESDAY...ESPECIALLY OFFSHORE...DUE TO GUSTY NORTHERLY
WINDS. THESE WINDS WILL ALSO BRING IN MUCH DRIER AIR...WHICH MAY
LEAD TO FIRE WEATHER CONCERNS FOR NORTH INTERIOR SECTIONS EARLY
NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY.

Thank You-We can certainly use the rainfall but do not want any of the rough stuff.

The storm popping in coastal southern Broward co is the one to watch. I wont be surprised if develops northward quickly

your welcome pat

We're lucky that this is not hurricane season as we could have been looking at a possible tropical system developing in the GOM. There has been a very intense convective burst building in the GOM. Just take a look at these satellite images.

Great news. Based upon satellite loops, if that convective burst maintains itself, it will move directly over Lake Okeechobee late this afternoon and will linger for several hours. Looks like rainfall rates near 3 inches per hour with this convection.

StormW that is exactly what i think is likely to happen. The deep waters have warmed to the point where upwelling isn't going to feed this La Nina much longer at all. The strengthening sun will warm the upwelled waters quickly as spring leads into summer. Then the SOI will drop like a rock as warm anomalies spread from both sides of the Pacific. Still I don't think it will be into El Nino until after this hurricane season is done. I think this hurricane season will be "La Nina to ENSO neutral" overall as it will take time for La Nina's effects to wane.

As I was telling Adrian last night, these "little" low pressure systems can strengthen quickly over the Gulf when there is ample moisture available.

This is quite interesting. Let me know what you see here.

ive been a member now for almost a year storm yes it very good site i really like features as well and the updating freqency is what i like the most every 4 to 6 mins with that radar and every 10 to 15 mins for sats

I have a question...

With all this flooding to the north, what does this mean for us along the Mississippi river here in south Louisiana? Any ideas when the river will crest here?

Might be interesting to take a peek over the levee.

CC, those winds indicate a stronger than expected surface low forming in the Gulf. The northeast side has the strongest winds but it has a definite closed circulation. (Thats what I see.)

168 Hmann. Unless there is more heavy rain further south, the Mississippi wont flood where you are. It will drain slowly south and its many tributaries and wide path will reduce the crest the further south you go.

I have a question...

With all this flooding to the north, what does this mean for us along the Mississippi river here in south Louisiana? Any ideas when the river will crest here?

Might be interesting to take a peek over the levee.

High river puts city on alert
Thursday March 20, 2008, 9:06 PMStory: Link

At 69W looks like the Bermuda high is in it's classic August position.

2008 Atlantic Hurricane Season Outlook

Issued March 20, 2008 by W456

Main Indicators

ENSO
Rainfall Patterns over Western Africa
The North Atlantic Oscillation (NAO)
The Quasi-Biennial Oscillation (QBO)
Continuations of above average activity

Overview of Indicators

During El Nino, high SST over the eastern Pacific causes more deep convection there. The resultant outflow aloft enhances upper tropospheric westerlies over the Caribbean and western equatorial Atlantic. Consequently, the 200 mb anticyclonic flow necessary for tropical cyclones to develop is reduced. During Neutrals and weak to moderate La Nina, low SSTs over the eastern Pacific suppress deep convection there. The resultant subsidence enhances lift and weak to moderate upper level easterlies over the Tropical Atlantic Summer, which favors tropical cyclone development.

West Africa represents the birth place of most Atlantic tropical cyclones. It is also the origin of the West African Dust outbreaks known as the Sahara Air Layer. Wetter than normal conditions over Sub-Shara Africa indicate wetter and cooler tropical waves decreasing the temperature gradient between the sea surface temperature and the 700 mb wave axis and suppressing convection. However, wetter than normal conditions also indicate reduce dust phenomena during the season. Drier than normal conditions produces hotter waves at 700 mb and as they move over the cooler sea surface temperatures, the temperature difference is enough to initiate convection which is needed for cyclogenesis. Though, drier conditions over West Africa means enhanced African Dust.

The Positive NAO index phase shows a stronger than usual subtropical high pressure center and a deeper than normal Icelandic low. The negative NAO index phase shows a weak and further centralized subtropical high and a weak Icelandic low. Negative NAO values imply more ridging in the central Atlantic and a warm North Atlantic Ocean due to stronger southerly winds during this period. Positive NAO values imply more ridging in the Eastern Atlantic and cooler sea surface temperatures especiallu along the West African Coast. A stronger ridge also indicate the probability of drier conditions over West Africa.

During the QBO, Atlantic tropical cyclones are more frequent when 30 mb winds are westerly and increasing, rather than easterly and increasing. There have been 44% more hurricanes and 74% more hurricane days during the west as opposed to east phase of the QBO.

Overview of Current and Extended Conditions

The current ENSO forecast calls for a weakening La Nina from now till June. During the months of May to August, temperature anomalies are forecast to be slightly cooler to near neutral conditions. Weak to neutral La Nina favor a slight increase in both the number of hurricanes and their intensity. These neutral conditions will extend into the remainder of the season up to November.

Over the past six months, there have been drier than normal conditions over Sub-Shara Africa which will indicate hotter and drier African Waves and increase Saharan Dust. Hotter and drier waves are more favored to produce convection as they enter the Atlantic and I believe this maybe the case between dust outbreaks. Also, a more eastward and stronger subtropical ridge (Positive NAO) will favor drier and dustier conditions and a more westward and weaker ridge (Negative NAO). Currently, the NAO index is near neutral but forecast to enter negative values this April which may indicate cooler Central Atlantic SSTs but warmer SSTs west of 60W and east of 30W.

The current tropical winds between 30 mb and 50 mb over the Tropical Atlantic are easterly and that corresponds to a 40 yr average between 1950-1999 of 8.53 storms. Atlantic tropical cyclone activity is inhibited during easterly phases of the QBO due to enhanced lower stratospheric wind ventilation and increased upper-troposphere-lower stratosphere wind shear. However, the trend of these stratospheric winds is decreasing and if this trend continues, the July 50-30 mb winds will enter a more weak easterly to weak westerly phase.

The Forecast

Based on the above information, adjustments to the normal seasonal average can be made. The 1950-2005 NOAA average is 11.0 named storms, 6.2 hurricanes and 2.7 major hurricanes. An addition of 2 storms for weak La Nina to Neutral. An addition of 2 storms for hotter tropical waves and subtraction of 1 storm for enhanced Saharan Conditions. An addition of 1 storm for negative NAO for April and an addition of 1 storm for expected QBO conditions. An addition of 1 storm for continuation of above normal tropical cyclone activity of past hurricane seasons

Preliminary Seasonal Forecast 16 named storms, 7 hurricanes and 3 major hurricanes.

Note: This forecast is subject to change and will be updated in May to inlcude SLP anomalies, 200 mb winds, 50 mb winds, sea surface temperatures and tracks.


Figure 1. CFS Seasonal Sea Surface Temperature Forecast


Figure 2. 6-month Accumulated Precipitation % of Normal

Seasonal Forecasts are not an Indicator of what will happen, Its a guess at best.

Another view of the CMC showing a 'cane near Florida:

Storm, I meant the GOM.

true pat its like pissing in the wind who knows where its gonna go

iam getting some 55dbz signutures n of keys just south of mainland which indicates storms reaching severe levels

Forecasts, the seasonal Hurricane types are full of Many Variables. A MIT Super Puter cant crunch all the numbers, lets alone a Human.
I never look at one..nor worry over them.
Following the real storms and Observing them in the real time is best to understands the Single storm.Let alone 6 months worth. And No one nor computer can get a Handle on upwelling trends in a future scenario. Thats why I focus on Impacts and aftereffects. It's where the science meets the coastline, and Humans.

i tell it like it is jfv i wont lie or make more of it than it is and when it comes to weather its a crap shoot anything goes
my moto is
it can and will change everytime

179. Patrap 11:49 AM AST on March 22, 2008
Seasonal Forecasts are not an Indicator of what will happen, Its a guess at best.

Well if that is the case, then that is my guess.

Thanks JFV

Great Job 456.

456, Post La Nina seasons have been bad for the Eastern Seaboard 4 times in a row. Think Hugo, Isabelle, Gloria for examples. Your forecast of a stronger Eastward Bermuda high seems to indicate the same thing. I don't ever focus on numbers of named storms but I think it will be average to slightly above average. Steering is the key. The I'm thinking early Carribean development would tend westward, the cape verde storms could be bad for the Carolinas, while late season Carribean development would tend towards Florida.

JFV, to answer your question, I've decided to hold back on my predictions since there are changes occuring now with La Nina and since I want to gather more data before I make them official predictions. I apologize for the delay.

Hello everyone! The gomex looks ripe today. Can anyone tell me what effect La Nina has on the upcoming tornado season? Living in the middle of "Tornado Alley" can make a person nuts sometimes. We are hoping to not repeat last year!

Interesting numbers, 456.

I don't think they are out of the ball park, IF the forecast conditions materialize. I think the key variable will be how much the La Nina moderates, and to what extent. If we are practically at El Nino by November, I'd be very surprised.

I'm also wondering how much of an increase in SSTs we will see between Jun and August. If we are in an ENSO-neutral state by Sept-Oct, warmer than usual waters in the MDO would mean major landfalling storms are more likely.