jeudi 2 octobre 2014
European Storm Forecast Experiment
Storm Forecast
Storm Forecast
Valid: Thu 02 Oct 2014 06:00 to Fri 03 Oct 2014 06:00 UTC
Issued: Wed 01 Oct 2014 22:02
Forecaster: GATZEN
Valid: Thu 02 Oct 2014 06:00 to Fri 03 Oct 2014 06:00 UTC
Issued: Wed 01 Oct 2014 22:02
Forecaster: GATZEN
A level 1 was issued for the south-west Medirterranean mainly for excessive precipitation,
large hail, and to a lower extend tornadoes.
A level 1 was issued for central and southern Italy mainly for excessive precipitation.
SYNOPSIS
Weak mid-level flow affects Europe on Thursday. A remaining of the south-west European trough over the Iberian Peninsula looses its connection to the northern short-wave trough that travels into Italy and the Balkans. Ridges build over France and Germany to Scandinavia as well as from the Aegean to Black Sea region. At lower levels, rather moist air is present over western and central Europe as well as across the Balkans, whereas dry air is affecting most of Scandinavia and eastern Europe. Rich moisture is located over the west Mediterranean. This is also the only region where steep lapse rates overlap with high moisture.
DISCUSSION
West Mediterranean
Near the base of the Iberian trough, lapse rates are quite steep as indicated by latest soundings. Additionally, profiles are moist with 0-1 km mixing ratios around 14 g/kg, yielding CAPE in the order of 2000 J/kg. Given north-easterly surface winds and a south-westerly flow above 850 hPa, strong vertical wind shear is expected over the south-western Mediterranean Sea.
Initiation is most likely near the base of the trough, where low-level convergence and weak capping is forecast. These slow-moving storms may produce excessive precipitation and locally large hail. Storms over Spain are expected to spread into the Mediterranean during the night as the trough moves eastward. Given strong vertical wind shear and high CAPE, an MCS is forecast. High precipitation is likely, together with locally large hail. Additionally, tornadoes are not excluded. Flooding will be the main threat along the north Algerian coasts and nearby mountains until the end of the forecast period.
Central Mediterranean
The trough axis of a short-wave trough moves east and crosses Italy on Thursday. Overnights thunderstorms across the Tyrrhenian Sea are forecast to spread onshore across Italy and also over Sardinia and Corsica. Weak lapse rates and vertical wind shear are present, so that well-organized storms are not expected. However, slow storm movement and moist air will allow for excessive precipitation with a threat of local flooding. Storms are forecast to spread south-east during the night hours and may affect the Ionian Sea late in the period.
large hail, and to a lower extend tornadoes.
A level 1 was issued for central and southern Italy mainly for excessive precipitation.
SYNOPSIS
Weak mid-level flow affects Europe on Thursday. A remaining of the south-west European trough over the Iberian Peninsula looses its connection to the northern short-wave trough that travels into Italy and the Balkans. Ridges build over France and Germany to Scandinavia as well as from the Aegean to Black Sea region. At lower levels, rather moist air is present over western and central Europe as well as across the Balkans, whereas dry air is affecting most of Scandinavia and eastern Europe. Rich moisture is located over the west Mediterranean. This is also the only region where steep lapse rates overlap with high moisture.
DISCUSSION
West Mediterranean
Near the base of the Iberian trough, lapse rates are quite steep as indicated by latest soundings. Additionally, profiles are moist with 0-1 km mixing ratios around 14 g/kg, yielding CAPE in the order of 2000 J/kg. Given north-easterly surface winds and a south-westerly flow above 850 hPa, strong vertical wind shear is expected over the south-western Mediterranean Sea.
Initiation is most likely near the base of the trough, where low-level convergence and weak capping is forecast. These slow-moving storms may produce excessive precipitation and locally large hail. Storms over Spain are expected to spread into the Mediterranean during the night as the trough moves eastward. Given strong vertical wind shear and high CAPE, an MCS is forecast. High precipitation is likely, together with locally large hail. Additionally, tornadoes are not excluded. Flooding will be the main threat along the north Algerian coasts and nearby mountains until the end of the forecast period.
Central Mediterranean
The trough axis of a short-wave trough moves east and crosses Italy on Thursday. Overnights thunderstorms across the Tyrrhenian Sea are forecast to spread onshore across Italy and also over Sardinia and Corsica. Weak lapse rates and vertical wind shear are present, so that well-organized storms are not expected. However, slow storm movement and moist air will allow for excessive precipitation with a threat of local flooding. Storms are forecast to spread south-east during the night hours and may affect the Ionian Sea late in the period.
mercredi 1 octobre 2014
Day 2 Convective Outlook
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1124 PM CDT TUE SEP 30 2014 VALID 021200Z - 031200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MIDWEST TO CNTRL TX... ...SUMMARY... BAND OF THUNDERSTORMS SHOULD FORM ALONG COLD FRONT AS IT PROGRESSES ACROSS THE PLAINS INTO THE MISSISSIPPI VALLEY. DAMAGING WIND GUSTS ARE THE PRIMARY SEVERE THREAT WITH THE STRONGEST STORMS. ...MIDWEST TO CNTRL TX... LOW LATITUDE SHORT-WAVE TROUGH WILL EJECT ACROSS THE SRN ROCKIES/HIGH PLAINS EARLY IN THE PERIOD BEFORE EJECTING RAPIDLY NEWD INTO THE LOWER OH VALLEY AFTER MIDNIGHT. PRIMARY FEATURE RESPONSIBLE FOR THIS RAPID EJECTION IS AN INTENSIFYING SPEED MAX THAT WILL DIG INTO THE CNTRL PLAINS BY 03/12Z. THIS SECONDARY FEATURE SHOULD AID DEEPENING CYCLONE/SHARPENING FRONTAL BOUNDARY OVER THE UPPER GREAT LAKES LATE. ALTHOUGH FRONTAL INTENSIFICATION IS NOT EXPECTED UNTIL LATE IN THE PERIOD...CONVECTION IS EXPECTED TO DEVELOP ALONG PROGRESSIVE BOUNDARY BEGINNING FAIRLY EARLY IN THE PERIOD. LATEST MODEL GUIDANCE SUGGEST AMPLE BOUNDARY LAYER MOISTURE WILL ADVANCE AS FAR NORTH AS NRN IL BY LATE AFTERNOON WITH PW VALUES AOA 1.5 INCHES. WHAT LITTLE CINH IS OBSERVED AT 12Z AHEAD OF THE FRONT WILL DIMINISH BY 17-18Z SUCH THAT THUNDERSTORMS SHOULD READILY DEVELOP ALONG WIND SHIFT ACROSS ERN KS/OK. THIS ACTIVITY SHOULD MATURE INTO A EXTENSIVE SQUALL LINE STRETCHING FROM THE MID MS VALLEY...SWWD INTO NERN TX BY LATE AFTERNOON. GREATEST BUOYANCY IS EXPECTED TO RESIDE FROM THE OZARK PLATEAU SWWD INTO TX AND HAIL IS MOST LIKELY ALONG THIS PORTION OF THE SQUALL LINE. MEAN SWLY WIND WILL BE ON THE ORDER OF 30-35KT...MORE THAN ADEQUATE FOR PROGRESSIVE SQUALL LINE THAT SHOULD ADVANCE TOWARD THE MS RIVER DURING THE EVENING HOURS. WHILE DEEP LAYER SHEAR IS MORE THAN ADEQUATE FOR DEEP ROTATION...STORM MODE FAVORS LINEAR DEVELOPMENT AND DAMAGING WINDS ARE THE PRIMARY SEVERE THREAT.
European Storm Forecast Experiment
Storm Forecast
Storm Forecast
Valid: Wed 01 Oct 2014 06:00 to Thu 02 Oct 2014 06:00 UTC
Issued: Tue 30 Sep 2014 21:27
Forecaster: PUCIK
Valid: Wed 01 Oct 2014 06:00 to Thu 02 Oct 2014 06:00 UTC
Issued: Tue 30 Sep 2014 21:27
Forecaster: PUCIK
A level 1 was issued for extreme S Spain towards NW Algeria mainly for large hail and severe wind gusts.
SYNOPSIS and DISCUSSION
No significant change to the macrosynoptic setup is forecast in the following 24 hours. A trough is expected to translate from France towards the Alpine area. To the southwest, a quasistationary trough will be persistent over W Iberia. To the north, a deep low pressure system is forecast to affect W Scandinavia.
Regarding DMC occurrence, we may identify two potential foci:
1/ Western Mediterranean. Here, the highest probability of CI will be present in the line from Corsica towards N Italy, where combination of approaching trough and weak frontal boundary should aid in the scattered to widespread tstm development. Rather marginal CAPE and weak vertical wind shear will likely preclude any more pronounced severe weather threat. To the southwest, better conditions will exist just offshore Algeria towards the Strait of Gibraltar and extreme S Spain. In this region, moderate to strong vertical wind shear along with steep mid-level lapse rates from EML should support well organised DMC, perhaps capable of large hail and severe wind gusts. However, questionable initiation precludes higher threat than Lvl 1.
2/ S Germany towards Bohemia and S Poland. In the wake of the cold front boundary, cool mid-level temperatures will contribute to the marginal CAPE build-up. Scattered tstms will be possible, but severe potential will be very limited due to the marginal instability and DLS below 10 m/s.
SYNOPSIS and DISCUSSION
No significant change to the macrosynoptic setup is forecast in the following 24 hours. A trough is expected to translate from France towards the Alpine area. To the southwest, a quasistationary trough will be persistent over W Iberia. To the north, a deep low pressure system is forecast to affect W Scandinavia.
Regarding DMC occurrence, we may identify two potential foci:
1/ Western Mediterranean. Here, the highest probability of CI will be present in the line from Corsica towards N Italy, where combination of approaching trough and weak frontal boundary should aid in the scattered to widespread tstm development. Rather marginal CAPE and weak vertical wind shear will likely preclude any more pronounced severe weather threat. To the southwest, better conditions will exist just offshore Algeria towards the Strait of Gibraltar and extreme S Spain. In this region, moderate to strong vertical wind shear along with steep mid-level lapse rates from EML should support well organised DMC, perhaps capable of large hail and severe wind gusts. However, questionable initiation precludes higher threat than Lvl 1.
2/ S Germany towards Bohemia and S Poland. In the wake of the cold front boundary, cool mid-level temperatures will contribute to the marginal CAPE build-up. Scattered tstms will be possible, but severe potential will be very limited due to the marginal instability and DLS below 10 m/s.
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