842 FXUS64 KLCH 062218 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 418 PM CST Wed Mar 6 2019 .DISCUSSION... Short Term [Today and Thursday] This afternoon's surface analysis indicates a 1032 hPa high pressure extends across the Lower Mississippi River Valley. Clear skies combined with daytime mixing and insolation have allow for temperatures to climb into the mid to upper 50s across most of the region this afternoon. The surface high pressure will move eastward during tonight into Thursday and result in becoming more southeasterly. These southeasterly winds will contribute to increasing moisture and cloud cover during the overnight hours. Therefore, temperatures are not expected to fall to 32 or below as in the past two nights. Overnight lows should range from the mid 40s along the coast to the mid 30s across northeastern portions of the CWA. Despite cloud cover tomorrow, temperatures are expected to continue to warm as southeasterly winds contributes to warm air advection across the area. Daytime temperatures should climb into the 60s across the entire area. In addition, moisture is expected to increase which will result in a chance for showers, mainly across southeast Texas in the afternoon into the evening. Long Term [Friday through Tuesday] A short wave trough will dig into the central Plains on Friday into Saturday which will help support cyclogenesis. This will result in strong low level height and surface pressure gradients across the region which will result in a strong kinematic wind field over the Lower Mississippi River Valley. Model guidance is indicating 0-6 km wind shear will be in excess of 45 knots. Meanwhile, effective helicity is forecast to be in excess of 250 m2/s2. These strong wind fields will result in the potential for organized convection and severe weather during the day on Saturday. The main question mark with regards to severe weather on Saturday will be the amount of instability that can develop ahead of the surface front. Steepening 700 hPa - 500 hPa lapse rates and dewpoints into the mid 60s will be supportive of a conditionally unstable environment developing. On the other hand, isentropic ascent will result in widespread cloud cover which will limit heating and destabilization. Despite the cloud cover, model guidance is still indicating the potential for MLCAPE of 1000-1500 J/kg which in conjunction with the aforementioned wind fields will certainly support at least the potential for severe convection across the area on Saturday. Based on this conditional threat, the Storm Prediction Center currently has the entire area highlighted in a Slight Risk of severe weather. However, the highest likelihood for severe weather occurring appears to be concentrated in the northern portions of the CWA into central Louisiana during the mid to late afternoon of Saturday. Continue to monitor the forecast over the next few days for updates on this potential severe threat. Beyond Sunday, a more amplified height pattern is forecast to develop across the CONUS into early next week. Two troughs are forecast to be centered over the East Coast and West Coast with a ridge axis centered just east of the Lower Mississippi River Valley. This will help induce return flow across the region during the early part of next week. As a result of this return flow, temperatures are expected to be above normal with chances of showers and thunderstorms on Monday and Tuesday. && .MARINE... Onshore flow will redevelop as high pressure moves east of the area. An increasing pressure gradient will result in these onshore winds increasing to 10 to 15 knots and remaining elevated through Saturday. These winds will become stronger Saturday ahead of a front pushing into the region and Small Craft Exercise Caution or Advisory products may be needed. Elevated rain and thunderstorm chances will accompany the front as it moves through the coastal waters Saturday. Easterly flow is expected to redevelop in the wake of this system and continue into early next week. && .PRELIMINARY POINT TEMPS/POPS... AEX 38 62 58 72 / 0 0 30 40 LCH 43 67 62 72 / 0 20 20 40 LFT 42 65 59 74 / 0 0 10 30 BPT 47 70 64 73 / 0 30 30 30 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...None. && $$ PUBLIC...26