Ernesto weakens; Florence forms; fires, historic heat wave in Oklahoma
Enigmatic Tropical Storm Ernesto continues westward across the Caribbean, but has weakened. Ernesto certainly looks impressive on visible satellite loops, with a symmetric shape, good spiral banding, and an upper-level outflow channel to the north and east. But this morning's flight by the Hurricane Hunters found that Ernesto had weakened, with top winds of just 50 mph, and a central pressure that had risen to 1008 mb. The storm is fighting low to moderate wind shear of 5 - 15 knots, and water vapor satellite loops show a large area of dry air to the west. Upper level winds from the west are driving this dry air into the west side of the storm. Ernesto's rains are staying just north of the ABC Islands, as seen on Aruba radar. The southern shore of the Dominican Republic is experiencing occasional heavy rains from Ernesto's spiral bands.
Figure 1. Morning visible satellite image of Ernesto taken at 8 am EDT, with echoes from a microwave satellite instrument in the 85 GHz band superimposed. Image credit: Navy Research Lab, Monterey.
Forecast for Ernesto
Ernesto continues to be a major challenge to forecast. Despite the seemingly favorable conditions for intensification expected today through Tuesday, with low wind shear, a moister environment, and increasing heat energy in the ocean, many of our top computer models refuse to predict intensification, and in fact, weaken the storm. Of the major dynamical models NHC uses operationally--the ECMWF, GFS, NOGAPS, UKMET, GFDL, and HWRF--only the NOGAPS and GFDL show Ernesto reaching hurricane strength in the Caribbean. The ECMWF dissipates the storm. However, some of the best statistical models, such as the LGEM and SHIPS, do show Ernesto becoming a Category 1 or 2 hurricane in the Caribbean. The official NHC intensity forecast of a Category 1 hurricane between Jamaica and Mexico's Yucatan Peninsula is a reasonable compromise, but the uncertainty in this is high. It would not be a surprise to see Ernesto mysteriously degrade, or undergo rapid intensification into a Category 2 hurricane off the coast of the Yucatan. Such is the state of modern hurricane intensity forecasting. Given that we don't have a very good idea of how strong Ernesto will become, making an accurate track forecast is hard. A stronger Ernesto will be more likely to feel the influence of a trough of low pressure moving to the north of the storm on Tuesday, which would pull the storm to the northwest into the Gulf of Mexico. This would likely result in a landfall in the U.S. A weaker Ernesto is more likely to head almost due west, resulting in a landfall Wednesday in Belize or Mexico's Yucatan Peninsula. This is the more likely solution, given the recent behavior of the storm.
Tropical Storm Florence forms
Tropical Storm Florence has arrived in the far Eastern Atlantic, marking the 3rd earliest date for formation of the Atlantic's sixth named storm. Only 2005 and 1936 had earlier arrivals of the season's sixth storm. The new tropical storm developed unusually quickly from a tropical wave that moved off the coast of Africa just two days ago, and the storm's formation was aided by a pulse warm ocean water and associated low pressure called a Convectively Coupled Kelvin Wave (CCKW.) The SHIPS model is diagnosing a moderate 10 - 15 knots of wind shear over Florence, and predicts that the shear will stay in the moderate range over weekend, then increase to the high range as Florence encounters an upper-level trough of low pressure. The latest Saharan Air Layer Analysis shows that a large area of dry air lies to the north and west of Florence, and this dry air will likely cause problems for the storm. Ocean temperature are near 26 - 26.5°C, which is right at the threshold for where a tropical storm can typically exist. The predicted steering current flow for Florence does not favor a long-range threat to any land areas.
Historic heat wave in Oklahoma
A historic heat wave and drought fueled raging fires on Friday in Oklahoma. The fires destroyed at least 65 homes, forced multiple evacuations, and closed major roads. Oklahoma City had its hottest day in history, hitting 113°, tying the city's all-time heat record set on August 11, 1936. The low bottomed out at 84°, the warmest low temperature ever recorded in the city (previous record: a low of 83° on August 13, 1936.) Oklahoma City has now had three consecutive days with a high of 112° or higher, which has never occurred since record keeping began in 1891. With today's high expected to reach 113° again, the streak may extend to four straight days. Yesterday was the third consecutive day with more than a third of Oklahoma experiencing temperatures of 110° or higher, according to readings from the Oklahoma Mesonet. NOAA's Storm Prediction Center (SPC) declared a "Critical" fire weather day over most of Oklahoma yesterday, due to extreme heat and drought, low humidities, and strong winds. Between 4 - 5 pm CDT Friday, Oklahoma City had a temperature of 113°, a humidity of 12%, and winds of 14 mph gusting to 25 mph. Another "Critical" fire weather day has been declared for Saturday. A cold front approaching from the northwest will bring winds even stronger than Friday's winds, and Oklahoma will likely endure another hellish day of extreme heat, dryness, and fires.
Figure 2. The Geary, Oklahoma fire, looking north, on August, 3, 2012. Image credit: Oklahoma City Fire Department. The Geary fire spawned a gustnado.
Only comparable heat wave: August 1936
The only heat wave in Oklahoma history that compares to this week's occurred in the great Dust Bowl summer of 1936, the hottest summer in U.S. history. Oklahoma City experienced three days at 110° that summer, and a record streak of 22 straight days with a temperature of 100° or hotter. Those numbers are comparable to 2012's: three days at 110° or hotter, and a string of 17 consecutive days with temperatures of 100° or hotter. It's worth noting that Oklahoma City has experienced only 11 days since 1890 with a high of 110° or greater. Three of those days were in 2011, three were in 2012, and three were in the great Dust Bowl summer of 1936. Clouds moved in over Tulsa, Oklahoma yesterday, holding down the high temperature to just 107°, ending that city's 3-day streak of 110°+ days. The only longer streak was 5 consecutive days on August 9 - 13, 1936.
Figure 3. Most of Oklahoma has experienced eight consecutive days with highs of 100° or more, and many regions, including Oklahoma City, have had a streak of 17 such days. Image credit: Oklahoma Mesonet.
Jeff Masters
Reader Comments
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I still must respectfully disagree. it is a 50 MPH TS. RI will not occur with dry air of this magnitude in front of it. Also it is moving WAY too fast for RI. Hurricane tomorrow maybe.
As it encroaches closer and closer to me...
You might want to make an appointment with the eye doctor. I see no northward jog. I see the central dense overcast expanding. Maybe that is throwing you off? That storm is tracking due west at the moment. And even if it did make a jog in the last two frames, which it didn't, a jog does not a course change make.
The storm is alternating between west and west-northwest.
NO I don't! It's straight WEST for now..., and in any case we have ALL have been here long enough to know that storms wobble - average motion it WEST!
280 degrees is north of due west, and looks good for a long-term average motion right now.
Doesn't a storm typically slow down a lot before a turn? I'm sticking with the GFS model for a Mexico landfall at the moment.
I would say that on average that would be more west than WNW
SHOWERS AND THUNDERSTORMS HAVE INCREASED IN ASSOCIATION WITH AN AREA
OF LOW PRESSURE CENTERED ABOUT 50 MILES EAST-SOUTHEAST OF CAPE
CANAVERAL FLORIDA. SINCE THE SYSTEM IS EXPECTED TO MOVE INLAND
LATER TODAY...FURTHER DEVELOPMENT IS NOT ANTICIPATED. HOWEVER...
LOCALLY HEAVY RAIN AND GUSTY WINDS ARE POSSIBLE ACROSS PORTIONS OF
THE FLORIDA PENINSULA TODAY AND SUNDAY. THIS SYSTEM HAS A LOW
CHANCE...10 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.
Internal reorganization. Cant use up energy producing wind and organizing at the same time,one or the other.
Can you post that image, please? Thanks!
"and you know this maaannnn!"
UW-CIMSS Automated Satellite-Based
Advanced Dvorak Technique (ADT)
Version 8.1.3
Tropical Cyclone Intensity Estimation Algorithm
Current Intensity Analysis
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm
----- Current Analysis -----
Date : 04 AUG 2012 Time : 164500 UTC
Lat : 14:29:21 N Lon : 69:10:39 W
CI# /Pressure/ Vmax
4.0 / 989.4mb/ 65.0kt
Final T# Adj T# Raw T#
3.6 4.1 4.1
Center Temp : -71.1C Cloud Region Temp : -70.1C
Scene Type : UNIFORM CDO CLOUD REGION
Positioning Method : FORECAST INTERPOLATION
Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC
Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : ON
Rapid Dissipation Flag : OFF
C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 66km
- Environmental MSLP : 1012mb
Satellite Viewing Angle : 18.3 degrees
If it becomes a hurricane tomorrow, it will not have passed Jamaica yet. I think a hurricane watch (if Ernesto continues to look good the next 3 hours) would be a good idea to give Jamaican's an idea that this could be a serious situation.... but I respect your dissenting opinion :)
agreed, as stated below, in the last 12 hours Ernesto has moved .5N and 3.1W; I think the westward movement depicted by the NHC is correct despite what many on here think lol
I didn't look at sat imagery yet to confirm or deny...But Ernesto did move more northerly per the last recon fix. If it is still moving WNW ish, then it is on the verge of being more than a jog.
I don't know how to post images but here is the link
Edit: Link didn't work so I tried to post the image. Hope it works.... but the loop would be better to show the dry air being pushed away, and I don't know how to post loops either :(
Ernesto Long Floater - RBTOP Color Imagery Loop
TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT SAT AUG 4 2012
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL STORM ERNESTO LOCATED OVER THE SOUTH-CENTRAL CARIBBEAN SEA...AND ON TROPICAL STORM FLORENCE LOCATED OVER THE EASTERN ATLANTIC OCEAN.
SHOWERS AND THUNDERSTORMS HAVE INCREASED IN ASSOCIATION WITH AN AREA OF LOW PRESSURE CENTERED ABOUT 50 MILES EAST-SOUTHEAST OF CAPE CANAVERAL FLORIDA. SINCE THE SYSTEM IS EXPECTED TO MOVE INLAND LATER TODAY...FURTHER DEVELOPMENT IS NOT ANTICIPATED. HOWEVER...
LOCALLY HEAVY RAIN AND GUSTY WINDS ARE POSSIBLE ACROSS PORTIONS OF THE FLORIDA PENINSULA TODAY AND SUNDAY. THIS SYSTEM HAS A LOW CHANCE...10 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.
&&
...
$$
FORECASTER BLAKE
It moved WNW or NW for a little bit. Wobbles and center relocations helped too.
Poll time:
A) Ernesto's' attempt to punch through the dry air
B) He is getting into the Olympic spirit and trying to swing himself northward
C) He is about to "walk like an Egyptian"
click Image for Loop
15 plus 270 = 285 degrees.
ROFLMAO!!!
CI# /Pressure/ Vmax
4.0 / 989.4mb/ 65.0kt
CIMSS ADT has it as a 75 mph hurricane lol
Emily 2005 track
Viewing: 451 - 501
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